How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Louie Your Own Question
Louie
Louie, Technician
Category: Consumer Electronics
Satisfied Customers: 12139
Experience:  25+ yrs. experience in the field and 5+ yrs. online, down to component level.
13948492
Type Your Consumer Electronics Question Here...
Louie is online now
A new question is answered every 9 seconds

I Have a yamaha RXV-671, with the issue PS PRT 135:H, what

Customer Question

i Have a yamaha RXV-671, with the issue PS PRT 135:H, what does that mean?
JA: How long has this been going on?
Customer: mhhm well this issue has come up after I replaced one of the channels on the amp
JA: What's the exact make and model of your television? And how long has this been happening with the channels?
Customer: its an AV Receiver: Yamaha RXV-671, and about two days.
JA: What troubleshooting have you tried?
Customer: Do you know what the error PS PRT 135:H means?
JA: The electronics expert can solve this for you. Anything else you want him to know before I connect you two?
Customer: no thats it thanks
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Technician about your situation and then connect you two.
Submitted: 11 months ago.
Category: Consumer Electronics
Expert:  Louie replied 11 months ago.

Hi and welcome to JustAnswer,

Thank you for the question and your patience. Should you still need assistance for information purposes only...

Initially, is the message "...PS PRT 135:H..." immediately displayed on plugging back in ? ...or after attempting to power on? ....or only after running Self-Diagnostic Function?

Customer: replied 11 months ago.
when i run self-diagnostic function
Customer: replied 11 months ago.
what exactly does the H at the end indicate?
Expert:  Louie replied 11 months ago.

I understand; PS PRT = power supply protection; a power supply issue likely on the 5V line.

H = logic / voltage is high.

Possibly a 5V regulator that has failed.

Customer: replied 11 months ago.
I measured around 5.07V at the output of the power supply board
Expert:  Louie replied 11 months ago.

Sorry, but which power supply board was checked please?

Customer: replied 11 months ago.
Video 2 Board
Expert:  Louie replied 11 months ago.

I understand and this would be the standby power supply circuit.

Please note that this 5.5V is present even if the Yamaha is just plugged (but not turned on) hence the standby +5V.

Since the suspect +5V line is detected when running the diagnostics (not just plugged in), then it would be any of the other +5V supply fed from the main transformer.

Do you have access to the schematics?

Customer: replied 11 months ago.
I do
Expert:  Louie replied 11 months ago.

Please see p. 142 grid L7 IC334, a +5V regulator.

Customer: replied 11 months ago.
ok I found it
Expert:  Louie replied 11 months ago.

A potential suspect.

Since would be checking, it would be to your advantage to likewise check for the presence & consistency of its mate, the -5V.

...and another +5 after IC333.

As well as resistor R330.

Customer: replied 11 months ago.
Ok now the only way to check these things is if it's powered up correct? But in order to access this board, the HDMI board has to be removed. IF the HDMI is removed, then I can't power it on ?
Expert:  Louie replied 11 months ago.

Technically correct; a case of the chicken and the egg.

A moment please, composing a workaround.

Customer: replied 11 months ago.
Also there is no R330 Resistor
Expert:  Louie replied 11 months ago.

Sorry, that should be R3304.

Expert:  Louie replied 11 months ago.

A workaround / bench test would need a small 1Ampere 6-0-6 transformer to feed AC-5/E/AC-5 pins of the connector. This is to simulate the supply from the main transformer.

Customer: replied 11 months ago.
mmh I don't have a transformer on hand.
Expert:  Louie replied 11 months ago.

Unfortunately, no other easy bench test method except to use a substitute transformer.

Incidentally, there is another +5V after IC457 on p. 136 and some other +5Vs

Customer: replied 11 months ago.
I can't really test this, until I get a small transformer?
Customer: replied 11 months ago.
Ok so How many Volts transformer do I nee?
Expert:  Louie replied 11 months ago.

6-0-6; i.e. 6VAC center tap

Expert:  Louie replied 11 months ago.

It would also help to get some alligator clips with wires similar to the products shown HERE.

Customer: replied 11 months ago.
ok so if i need to get a centre transformer because I need an earth connection as well ? http://www.jaycar.com.au/6-15v-30va-2a-multi-tapped-transformer/p/MM2004 Would this work?
Expert:  Louie replied 11 months ago.

Please consider HERE also from Jaycar but higher current 1Ampere not just 150mA.

Customer: replied 11 months ago.
would 150mA work thouhg?
Customer: replied 11 months ago.
http://www.jaycar.com.au/12-6v-ct-7va-500ma-centre-tapped-type-2853-transformer/p/MM2013, so this is acceptable it's 500mA max?
Expert:  Louie replied 11 months ago.

Yes should work though the voltage may dip a bit.

Customer: replied 11 months ago.
where do i connect this transformer to test IC457?
Expert:  Louie replied 11 months ago.

IC457 would need a 12V supply. Aside from the above transformer, an 1N4001 diode would also be needed. Use the 6-6 of the transformer to get 12V + the diode and the result would be 12VDC fed to the IN and COM of IC457.

Customer: replied 11 months ago.
Ah fe, will a half wave rectifier do the trick, as the ripple will be pretty high ?
Expert:  Louie replied 11 months ago.

Agree but since we're just after the output voltage, should do the job for test purposes.

Customer: replied 11 months ago.
Ok well apart from those, what else should I check?
Expert:  Louie replied 11 months ago.

There are other voltages derived from these +5V (such as the 3.3, 1.8, 1.3) but for the moment, checking these 5V would do.

Of course, please note that a short at the output of a regulator would also cause the 5V to go down or the output to short to the input.

Customer: replied 11 months ago.
Ok I shall get the transformer and let you know. What would be the minimum acceptable value for these regulators ?
Expert:  Louie replied 11 months ago.

The regulator as its name/description implies would always be the same +5V output irregardless of the input voltage (as long as more than 5V) and/or the current drawn from it.

Simply, it should output 5V always (or thereabouts); no minimum/no maximum.

I have to add that it would be to your advantage likewise to re-do the solder in case of a cold solder on the pins of the regulator as well as the other components around it.

Customer: replied 11 months ago.
Ok so just to re-iterate, check IC334, IC333 and IC457 as well as R3304?
Expert:  Louie replied 11 months ago.

Yes; ...R3304 of course can be checked with just the Ω function of the multi-meter.

Customer: replied 11 months ago.
which pins should I measure between for IC334?
Expert:  Louie replied 11 months ago.

This is tricky; measure 12V supply between pin 1 and 3. Measure the output between pins 2 & 3. Expected is +5V but only if pin 4 is triggered with a separate +5V.

Customer: replied 11 months ago.
Hi Louie,
For measuring IC334, should the triggered +5V be a DC value, correct?
Expert:  Louie replied 11 months ago.

Yes; a + or a - sign before the voltage value would denote that it is a DC voltage.

Ideally, an external +5V source but if IC333 checks good first, its +5T output would also serve the purpose of triggering pin 4 of IC334.

Customer: replied 11 months ago.
ok well i check R3304, and it's reading a deat short.
Expert:  Louie replied 11 months ago.

To be expected or nearly so; it is 0.22Ω

Customer: replied 11 months ago.
well does that mean it's the problem?
Expert:  Louie replied 11 months ago.

No; it's good.

Customer: replied 11 months ago.
really because it's not reading anywhere near it's value?
Expert:  Louie replied 11 months ago.

It would really depend on the sensitivity of the meter; but 0.22Ω is nearly a short.

Incidentally, resistance values are preferably measured out-of-circuit.

Customer: replied 11 months ago.
IC333 had an input of 3.89V and an output of 3.64V
Expert:  Louie replied 11 months ago.

What is the input AC Voltage of the bridge diode D3304 please? ...and what is its output DC Voltage?

Customer: replied 11 months ago.
On which board?
Expert:  Louie replied 11 months ago.

Please see p.145 grid I8 VIDEO (1) board.

Customer: replied 11 months ago.
ok should I test it , with the 6VAC transformer?
Expert:  Louie replied 11 months ago.

Yes please; connect the transformer. The 6-0-6 transformer would power IC333 and IC334 through bridge diode D3304. 6-0-6 to be connected to AC-5/E/AC-5 pins.

Customer: replied 11 months ago.
ok so on the input the cetnre two pins 0.650V AC and ouput 4.18V DC
Expert:  Louie replied 11 months ago.

Sorry, confused.

What is the ACV from first yellow wire to the white wire? ...second yellow wire to the white wire? ...first yellow wire to the the second yellow wire?

Customer: replied 11 months ago.
ok between the first Yellow and White = 4.64V AC and between the second Yellow and White =4.61V, on the AC side of the rectifier = 6.67V AC and the output DC side = 9.23V DC
Expert:  Louie replied 11 months ago.

A bit low but should still work. Then the inputs of IC333 and IC334 should both be this 9.23V DC.

Customer: replied 11 months ago.
What else could be wrong?
Expert:  Louie replied 11 months ago.

Witn an input of 9.23V DC, the output of both ICs should be 5VDC subject to the description above.

What are the readings please?

Customer: replied 11 months ago.
ok on the output of IC333 i'm getting 3.36V and on the input of the regulator 4.63V
Expert:  Louie replied 11 months ago.

What is the DC Voltage across C3309 ? ...how about across C3310?

Customer: replied 11 months ago.
Can I measure at J4142 with refrence to earth? Or do I have to measure at the capacitors themselves?
Customer: replied 11 months ago.
Also is there a way to disconnect connector CB02 from operation(2) board?Thanks
Expert:  Louie replied 11 months ago.

Yes, J4142 and J4141 links the + of bridge diode D3304 to the + of capacitor C3309 and eventually to IN pin of CIC333.

Customer: replied 11 months ago.
Hi louie,
When i power the device now, i get the error. ps prt 61L
Expert:  Louie replied 11 months ago.

Voltage is low (or missing) on PS1. See p.61

Customer: replied 11 months ago.
Ok so how do i go about it testing?
Expert:  Louie replied 11 months ago.

The same way the +5 were checked but this time, test for -5 and the other voltages as listed right of PS1. See p. 139

Customer: replied 11 months ago.
Sorry what chips are those again?
Expert:  Louie replied 11 months ago.

Is everything connected / assembled back?

Customer: replied 11 months ago.
Yess
Expert:  Louie replied 11 months ago.

I understand.

As posted above, for starters see p. 139 grid location G8, regulators IC101 and IC102.

Customer: replied 11 months ago.
IC101 and IC102 are on the main board? So how do I power up that board?
Expert:  Louie replied 11 months ago.

Hi again and appreciate your kind understanding; mobile with sluggish Internet.

Use the above proposed alligator clips with wires to connect D1041 to the main transformer.

Customer: replied 11 months ago.
Wait so power it up with the main transformer?
Customer: replied 11 months ago.
Also C3309 and C3310 had voltages of 5.27V and 5.23V respectively.
Customer: replied 11 months ago.
Ok so before this error came, we replaced one of the channels, however initially the insulator wasn't put correct and it was shorting out causing that transistor to smoke a few times. We fixed that problem and it's no longer shorting. With a quick multi metre test that transitor seems to still read, however it still has burnt marks on it. Not sure if that's the problem. Also if we just snip the leads of that, will it still work? It's the C4458 transistor on SBR channel.
Customer: replied 11 months ago.
OK plugged it back in again. PS2 PRT : 61L error still.
Expert:  Louie replied 11 months ago.

Appreciate the background information on the previous work done.

Still, what is more significant is the error code pinpointed that it is a power supply issue.

Interestingly, that the power supply circuit has initially a fault of PS PRT 135:H and then changed to PS PRT 61:L makes me suspect more of a loose wiring/connector or even a cold solder and no real component has failed.

As posted above; "...Voltage is low (or missing) on PS1...." -> ACBL, AC12, AC5, ±7, +3.3, -5VA.

Re-check connections to the board from the transformer and the solder points of the MAIN board p. 139 and VIDEO board p.142

Customer: replied 11 months ago.
Hi Louie,There are no cold solder joints oh no lose connections either. I have no idea what to do.
Expert:  Louie replied 11 months ago.

Consider a careful bench test for the different voltages cautiously using the alligator clips with wires to connect the main transformer to all the connectors of the MAIN and VIDEO boards.

A friendly reminder: voltage measurements by its very nature requires that the main transformer is powered up and therefore the circuit is LIVE! Please exercise due care and caution.

Customer: replied 11 months ago.
Hi Louie,So the error PS PRT 135H is still present. However when I went to check the 12V rail at connector CB456 (operation 2 board p.g. 104), I measured the values -11.07V and +12.89V for the -12V and +12V rail. So clearly this isn't correct. So do you have any suggestions of how to proceed ?
Expert:  Louie replied 11 months ago.

These -12V and +12V are also produced by IC102 and IC101 (p.139). Measure the voltages at the output pins of these regulator. If the same then, there would be no issue.

On the other hand, if the voltage at the output pins of these regulators are different than "...-11.07V and +12.89V...", then there is an issue along the wires/connections from these 2 regulator to the Operation (2) board.

Customer: replied 11 months ago.
ok, so how would I power up this board? As IC101 and IC102 are on the main board
Expert:  Louie replied 11 months ago.

Sorry, which "...power up this board..."; Operations (2) or Main (1)?

Customer: replied 11 months ago.
How can I test IC101 N IC102?
Expert:  Louie replied 11 months ago.

I understand and as posted before; "...Use the above proposed alligator clips with wires to connect D1041 to the main transformer..."

Customer: replied 11 months ago.
D1041 is already connected to the mains transformer, through CB102?
Expert:  Louie replied 11 months ago.

Yes; I was under the impression that the boards were disconnected.

Customer: replied 11 months ago.
Ok, because in order to access D1041 I need to remove the HDMI board and without the HDMI board the unit wont power on. So i'm not quite sure what you mean ?
Expert:  Louie replied 11 months ago.

Oh....cautiously jumper the switching contacts of relay RY371 (p.143 / grid C7) . Doing so would force the main transformer to turn on hence all the secondary of the main transformer would have power including "...D104...through CB102..."

Customer: replied 11 months ago.
Ok so if i jumper those pins together, as soon as I plug the amplifier into the wall, the system should turn on ?
Expert:  Louie replied 11 months ago.

Not necessarily fully turn on; BUT, there would be power to those connected thus "... test IC101 N IC102..." can be performed.

Please ensure no loose wire or any that may cause a short.

Customer: replied 11 months ago.
ok i tried using a resistor across the switching contacts but it just smokes every time i turn on. What do u think i should use to jumper those relay switch contacts?
Expert:  Louie replied 11 months ago.

The resistor would expectedly burn as it is unable to carry the onrush of current drawn by the transaformer.

Jumper with short lengths of electrical wire and a 2.0 A fuse

Customer: replied 11 months ago.
Ok IC101 is reading +12.3V and IC102 is reading 8.74V. However if I measure IC102 with respect to IC101's COM point im measuring -11.5V. But then if i measure IC102 with respect to it's own COM point im measuring -8.74V.
Expert:  Louie replied 11 months ago.

The pinout of IC101 is different with IC102. Please click HERE and HERE.

Customer: replied 11 months ago.
Ok IC101 is +12.03V and IC102 is -11.95V . Now if I measure CB456 (operation 2 board) I get +12.14 and -11.84V
Customer: replied 11 months ago.
But before when i measured at CB456 with everything plugged in I got -11.07V and +12.89V respectively.
Expert:  Louie replied 11 months ago.

It is surprising that the regulator outputs +12.03V but CB456 reads +12.89. The voltage would have to come from somewhere

or

there is a ground issue between the boards.

It is expected that voltage can go down from -11.95V to -11.84V but not -11.07V . It is either the regulator is not performing well

or

there is a load/part attached to the - supply line that is drawing too high a current thus forcing the voltage to dip.

Does the IC102 heats up faster/hotter than IC101?

Customer: replied 11 months ago.
Ok so I bought the whole amp back together and measure the voltage at CB456 (operation 2 board) and got -11.6 and +12.3V respectively. However now I'm getting PS2 PRT : 66L. So something is going wrong here.
Expert:  Louie replied 11 months ago.

Based on "...has initially a fault of PS PRT 135:H and then changed to PS PRT 61:L..." and then "...PS PRT 135H is still present..." back to "...PS2 PRT : 66L...", then yes; something is wrong and as posted before, it would appear likely to be a connection, wiring or even a solder issue but definitely intermittent.

Bear with me as the only approach would be to review the wiring, connections and solder points particular of the power parts; i.e. those that carry the power/voltages (not the signal parts).

Customer: replied 11 months ago.
Ok well If i disconnect the big grey connector (R189 from the HDMI board which connects to the Main Board), the error goes from H to L. I'm also given to understand that connector carries the signal for PS2 PRT
Expert:  Louie replied 11 months ago.

Let's look at the HDMI board.

Please see p. 91. These are the different regulators that would warrant checks.

Likewise of interest then would be the capacitors coupled to their outputs.

Customer: replied 11 months ago.
Ok which ones should I check ?
Expert:  Louie replied 11 months ago.

All since all have their inputs from the same source.

Customer: replied 11 months ago.
Sorry I can't find the schematic. Can u give me the name of one of the IC's?
Expert:  Louie replied 11 months ago.

IC65, IC6, RP130Q501D, R1172H501D, IC945, IC946, IC26 and IC930

Customer: replied 11 months ago.
IC930 has +4.52 on the output and +5.5V on the input. Should this output not be +3.3V?
Expert:  Louie replied 11 months ago.

Yes, the +5.5V input would be the same to all others.

And likewise yes on the +3.3 expected output.

The +4.52 is an over-voltage hence would cause fault in the circuit that it feeds.

Strongly consider a replacement.

And further bear with me as I would be mobile again shortly; 500+KM trip.

Customer: replied 11 months ago.
Hi Louie,
Before i purchase that IC are there anymore that i should check on that board?
Also RP130Q501D, R1172H501D are not specific ICs but simply part numbers of the already mentioned Ics correct?
Expert:  Louie replied 11 months ago.

Yes on RP130Q501D and R1172H501D as the Part Numbers on some of the regulators. There are others such as IC65 / NJM2888 for +5HT1

Please review pp. 127-134 of the Service Manual for the actual Part Numbers of the other regulators.

Customer: replied 11 months ago.
Hi Louie ,I tried to measure the voltage +5A which is at connector CB944. When I measured it with respect to the case ground i got a few mV. Then I tried to measure it with respect to DGND and I still got a few mV. This value needs to be +5V correct? Also the +5A pin is the 4th pin from the right correct?
Customer: replied 11 months ago.
Also where can I measure -VP ?
Expert:  Louie replied 11 months ago.

+5A is produced by IC457. Please see p. 138 grid J5

-VP is produced by Q4085. See p.137 grid G6

Customer: replied 11 months ago.
ok so IC457 is reading 0.641V. Does this mean it needs to be replaced? Also does this account for IC930 having an output voltage of +4.52 ?Thanks
Customer: replied 11 months ago.
Also note that the input V to IC457 is around 3.34V
Expert:  Louie replied 11 months ago.

The input of IC457 should be +12V and is fed from from the output of IC101 through resistor R4293.

No, the input of IC930 is a different +5V source. If present, then its output should be +3.3V

Customer: replied 11 months ago.
I've measured IC101 before and gave me a voltage of +12.03V
Expert:  Louie replied 11 months ago.

If "... IC101...+12.03V...", then "...input V to IC457..." should be +12.03V also.

If not and as measured 3.34V, then a connection issue or resistor R4293 as posted above may have failed or went high value.

Customer: replied 11 months ago.
I just measured R4293 and it was 21.5 ohms. So that's good as well.
Customer: replied 11 months ago.
the voltage across that resistor is 3.34V.
Expert:  Louie replied 11 months ago.

I understand;...then likely a connection issue.

Customer: replied 11 months ago.
How do you suggest I verify this?
Expert:  Louie replied 11 months ago.

What is the voltage before and after the resistor please?

Customer: replied 11 months ago.
Ok so before meaning, I measure it at IC101 ? And after I measure across the input of IC457 ?
Expert:  Louie replied 11 months ago.

The easiest would be to measure the voltages at the 2 ends of the resistor itself.

Customer: replied 11 months ago.
Ah so you mean measure across it ?
Expert:  Louie replied 11 months ago.

Sorry but no; that was done already "...voltage across that resistor is 3.34V...".

Black probe to common ground, red prove to 1 end of the resistor __V?

Black probe still to common ground, red prove to the other end of the resistor __V?

Customer: replied 11 months ago.
12.17V at one end and 3.34V at the other end
Expert:  Louie replied 11 months ago.

Is the resistor hot?

Customer: replied 11 months ago.
I can't tell as I'm only measuring behind it.
Customer: replied 11 months ago.
Tomorrow I'll take the HDMI board and force power it on, and confirm if its getting hot. From what we measured it sounds like that resistor has gone.
Expert:  Louie replied 11 months ago.

I would beg to differ based on "... R4293 and it was 21.5 ohms..."

I am more inclined to suspect IC457 (most likely) and/or +12A is loading the resistor/+12V line (least likely) or C4288 (just a possibility).

Customer: replied 11 months ago.
OK. How would you suggest I proceed, to get a definite cause for this issue ?Thanks
Expert:  Louie replied 11 months ago.

Disconnect jumper J4186 or de-solder / remove IC457. Then re-test the voltages of the resistor. If the 3.34V shoots up to 12, then IC457 is faulty.

Customer: replied 11 months ago.
Ok thanks. I shall try this tomorrow. Also since the +5A voltage is monitored by PS2 PRT. Should this solve the problem of PS2 PS PRT 61L ?Thanks
Expert:  Louie replied 11 months ago.

Likely yes as 61L is indicative of a low or missing +5V

Customer: replied 11 months ago.
ok . Hopefully this solves the problem.Thanks
Expert:  Louie replied 11 months ago.

Cheers.

Customer: replied 11 months ago.
Now, when I remove IC457 and measure the voltage across the resistor. Should I plug the HDMI board back in ?
Expert:  Louie replied 11 months ago.

I was under the impression that the voltage measurements done on IC457 and resistor R4293 were without the HDMI board installed/connected.

Is this not so?

Customer: replied 11 months ago.
No. I made this measurements with everything connected and the unit powered on. (Well i had to remove the protection to do so). Should I remove the HDMI board and repeat these measurements ?
Expert:  Louie replied 11 months ago.

Repeat please. The same as how it was done now; with everything connected except the regulator or jumper.

Customer: replied 11 months ago.
ok. I shall remove the HDMI board and force the relay on, then repeat the measurements.
Expert:  Louie replied 11 months ago.

...and would look forward to an update when able.

Customer: replied 11 months ago.
Ok so across each end of the resistor and GND we're getting 12.31V at both ends. But measuring across the resistor we get nothing. So i assume IC457 needs to be replaced ?
Customer: replied 11 months ago.
Ok I tested IC457 with a computer power supply, and I'm getting 5.13V at the output. So thats working.
Expert:  Louie replied 11 months ago.

Interesting....let's recap:

  • with IC457 still soldered in, resistor R4293 shows 12.17V at one end and 3.34V on the other end;
  • input V to IC457 is around 3.34V;
  • with IC457 removed, resistor R4293 shows 12.31V at both ends;
  • tested IC457...5.13V at the output.

With the unit unplugged, test the resistance to ground of J4178 (p. 96 grid G4)

Customer: replied 11 months ago.
ALSO that capacitor is good. And yes that's all correct. However the voltage across the resistor Is almost 0, with ic457 removed.
Expert:  Louie replied 11 months ago.

voltage across the resistor Is almost 0, with ic457 removed - is to be expected hence good.

J4178's resistance to common ground please?

Customer: replied 11 months ago.
It's short to GND. I attached a pic of where I measured it.
Customer: replied 11 months ago.
As a result the resistance bwtween the output and common terminals of IC457 is almost zero (short).
Expert:  Louie replied 11 months ago.

Agree a short at he load hence the input voltage is brought down;....should not be.

Please repeat/confirm resistance with jumper J4173.

Customer: replied 11 months ago.
Should I measure it at the point indicated in the picture I sent?
Customer: replied 11 months ago.
If so the resistance is 2.8 ohms
Expert:  Louie replied 11 months ago.

"...the resistance is 2.8 ohms..." which please J4173?

Customer: replied 11 months ago.
J4173. Also the resistance across C4278 is almost zero (short). Hence shorting the output to GND. Is there a replacement for that part , as its very small.
Expert:  Louie replied 11 months ago.

Surprising that C4278 is shorted. Was this resistance check done with C4278 out-of-circuit / de-soldered ?

Customer: replied 11 months ago.
in circuit.
Expert:  Louie replied 11 months ago.

Doubtful then; still, please consider repeating the test on C4278 out-of-circuit.

Customer: replied 11 months ago.
well if c428 isnt the problem, what else should I test?
Customer: replied 11 months ago.
Ok C428 isn't a short. But the tracks on either side of the capacitor is shorted together, for some reason.
Expert:  Louie replied 11 months ago.

Test / follow J4178, J4176, J4173 then to where CB460 is connected to...

...and it will lead us back to CB944 where you found out first the missing +5A. This test point if checked with resistance would most likely show very very low Ω.

Then locate and carefully de-solder / remove L9401. Test again for short where the +5A was originally found low/missing. Then test resistance of pin 11 of IC941.

Customer: replied 11 months ago.
Ok sorry. So do I test the resistance of those links to ground ? Then I test the resistance of +5A to ground?
Expert:  Louie replied 11 months ago.

Yes please; always with respect to the common ground.

The fault is too low resistance or even a short of the +5A to ground and we have to find out which component causes this low Ω reading.

It is rightful to suspect the capacitors as well but must be tested always out of circuit.

Personally, I use tweezers when handling SMDs.

Customer: replied 11 months ago.
Hi Louie,I can't seem to find the inductor L9401?
Expert:  Louie replied 11 months ago.

Please see p. 92 grid B3

Customer: replied 11 months ago.
Well see there's a short between the point 5A and GND without the HDMI board even connected.
Expert:  Louie replied 11 months ago.

Tested on CB460?

Customer: replied 11 months ago.
No I tested it on CB460, at the pointed indicated in the picture. Where should I check on CB459?
Expert:  Louie replied 11 months ago.

De-solder / remove all the jumpers; J4178, J4176, J4173 and test resistance to ground of all the now empty solder holes.

Can you also please re-check the empty solder points of the removed IC457.

Might as well check D4203.

Customer: replied 11 months ago.
Hi Louie,Do i take of each of the links one by one and check there resistance, or do I remove all of them at once then check there resistance at each hole ?
Customer: replied 11 months ago.
Hi Louie,Please refer to the attached picture, in which I've labeled the points in which have a low resistance (short).
Expert:  Louie replied 11 months ago.

Appreciate the image.

With J4176 & J4178 removed, then please check or even temporarily remove (also) C4252 and then J4177. After each removal, determine if the "...points...have a low resistance (short)..." would still persist.