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Louie, Customer Service
Category: UK Electronics
Satisfied Customers: 11943
Experience:  25+ yrs. experience in the field and 5+ yrs. online, down to component level.
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Grundig Satelit 800 PLL drift After tuning to a station,

Customer Question

Grundig Satelit 800 PLL drift
After tuning to a station, the frequency slowly drifts away.
Is there an adjustment to the PLL to make it more stable?
Submitted: 11 months ago.
Category: UK Electronics
Customer: replied 11 months ago.
By the way, I am an EE and can handle repairs, tuning, adjustments as necessary. Without schematics, etc, it is a bit difficult to troubleshoot. Your guidance will be helpful.
Expert:  Pete replied 11 months ago.
Hi Bob,Frequency drift is considered normal on most shortwave radios.There isn't anything you can do with this particular model to improve it, except perhaps to fit an external antenna.The radio already has Synchronous detection and AGC.Some more expensive radios have a drift lock feature, which allows them to precisely tune and lock onto a particular frequency, so drift is virtually eliminated. The Satellit 800 doesn't have this feature.
Customer: replied 11 months ago.
Sorry, this is not the normal drift one might experience on a short wave receiver. The drift begins immediately and within a minute it is off frequency and has to be returned. It is connected to an external antenna. Drift occurs on FM broadcast band as well. It should hold a station on the FM band.
Expert:  Pete replied 11 months ago.
If both AM and FM are affected then I would suspect a problem with the tuning knob - try removing it and cleaning behind it.Watch it closely to see if it moves very slightly after you let it go once a station has been tuned.
Customer: replied 11 months ago.
Don't think you understand. The FM broadcast band should be able to hold the tuning, but after a minute or two the frequency is completely off station. Even a cheap FM radio doesn't drift off station on the FM band 88 - 108 MHz.
Customer: replied 11 months ago.
IThanks I'll try that and let yo know. The knob isn't turnith though. The drift continues and never stope even if left on for weeks without touching the knob. Be back to you after cleaning behind the knob.
Expert:  Pete replied 11 months ago.
Ok, let me know how it goes...
Customer: replied 11 months ago.
After removing and cleaning the Knob as you suggested, the tuning continues to drift on al bands even with the knob removed completely. I would think that the problem is in the feedback loop or the phase detector of the PLL, Phase Locked Loop. Without a schematic, I don't know where to look or even if there is an adjustment.Do you know how or where I can get a schematic?
Expert:  Pete replied 11 months ago.
I haven't been able to find a schematic for this particular model - let me check if another expert can assist you further with this...Pete.
Customer: replied 11 months ago.
Customer: replied 11 months ago.
How are you coming with finding someone who can answer my original question and provide some help?
Expert:  Louie replied 11 months ago.
Hi Bob and welcome to JustAnswer,Thank you for the question and your patience. Should you still need assistance for information purposes only...Initially and other than the PLLs, proposed potential suspects for checking then (if have not been done):• base oscillator circuit particularly the reference crystal (most likely);• VCC line +5REG supply (least likely).
Customer: replied 11 months ago.
Although I am a EE and have many years experience in electronics, this doesn't help. I know the theory, but don't have access to documentation, schematics and the like. What I need is a schematic or point me to adjustments or specific replaceable modules, chips, etc.Appreciate whatever you can provide.
Expert:  Louie replied 11 months ago.
Bob,I only have electronic copies of the Asian (Chinese) equivalent (clone) which includes the wiring, block, exploded and more importantly schematic diagrams. BUT the insides particularly the PLL unit is that of a Satellit 800.As per site policy, I can offer these as an (additional) "Premium Service"Would these serve your purpose please?
Customer: replied 11 months ago.
Appreciate your response and not interested in upgrading service or paying more. So in short, thanks for your response and since neither you or Pete have provided any information pertinate to my initial question please refund myPay Pal account.Again thanks to you and Pete.
Expert:  Louie replied 11 months ago.
For billing & payment concerns, please contact Customer Service.