Screeching audio on Philips VR2022

[collisr]

Hi all,

Picked up 3 1st gen Video 2000 machines last week (2xVR2011,1xVR2022). The VR2022 is in nice condition and trying to get it up and running. It even had the remote and aux(AV) out add-ons!

After some "cleaning and oiling", it is working well, but has one issue:
- After being switched off for more than about a day, the first 30 mins (or so) of play results in a high-pitched squealing/screeching sound in the audio. After 30mins, the audio improves and after 1hr it is perfect until I power off the machine for the day.

I have swapped the audio board (U160) from the other machines (the part numbers are the same) but with the same result.

Anyone experienced this? I was going to replace the capacitors in the U160 audio board, but if multiple copies of the boards are giving the same issue, is the problem outside the audio board?

Any help gratefully received.

Rob

[Maarten]

Could be a capacitor on the power supply or a mechnical vibration in the deck.

[dj_fivos_sak]

This indicates bad power supply caps. Try using a heat gun on the power supply while the machine is running and see if the audio improves.

[space_charged]

The screech could well be electronic in origin as others have suggested. Caps in old power supplies are always suspect, but I'm wondering if there might be another cause.

I have known tape recorders to screech like that as a result of dirt on the tape path and in particular the rec/playhead. V2000s use a separate conventional tape head for their audio. Try giving it a clean.

Oscillation and vibration on the tape can also be caused by the capstan/pinch roller. On a video recorder also on the head drum. The video heads are VERY fragile and also mounted on the quartz "bimorphs". Great care is required when cleaning a head drum.

Charles

[collisr]

Thanks all.

I have some spare power supply boards that I can try. The audio seems to ALWAYS become perfect after about 30mins-1hr of playing so agree it appears to be capacitor related, but not sure where.

Will report back.

Rob

[Sanbeta]

Hi
After seeing your post I thought I'd shoot a message to you (not literaly).

I've been sent a lovely Philips VR2022 to sort for someone with one issue NO sound.
I have checked the caps to the sound board and only one was very lightly high.
I've also checked the other boards apart from the PSU.
This seems to have had really light usage as it's in lovely condition.
I also removed the cover to that rear socket that apparently you can get a plug in BNC/phono board for and there is power to some connectors with sound noise to the TV when probed. This would signify sound ouput from there.
I believe the issue to be in the RF section.
Would you be able to send any boards for me to swap over to narrow down where this issue is coming from?
I would be happy to pay you for your troubles.
You don't know where I could obtain that plug output as this would bypass the RF altogether. Have you a picture or number of sad part?

Many thanks in advance.

.......Kevin

[collisr]

Sent you a PM Kevin.

Still struggling with this problem - update. Tested/replaced all the electrolytic caps in the PSU board - no change; the machine still outputs a distorted/screeching audio on both RF out and AUDIO out (through the original expansion adaptor). Last week, the screeching would subside after about 60 mins of use, but now the screeching remains permenantly.

Checked the caps on both the audio board (U160) and IF Module (U40) and replaced a couple of caps that were a little off - no change.

Connected up another VCR as RF-input to the VR2022 and tuned in to see if a looped through signal (not involving the audio heads) would be any different. When I did this, there was virtually no audio at all. No screeching either, but a very faint audio only. Not sure what this tells me.

Any ideas?

[Grubhead]

Are there any static sensitive IC's on the audio board? They could have failed on both boards you tried. Unless you can prove that a one of the boards is working, I would put it down to one of them.

[collisr]

Thanks Grubhead - that was one of my first thoughts. But I have tried 3 separate audio boards and each time, the result has been identical.

Possible that each one has had an IC failure, but I would have thought that was very unlikely.

Very puzzling...

[collisr]

Hi again. Wanted to provide an update on this issue, which is becoming more puzzling.

My understanding is the audio chain on the VR2022 is "Audio Head"->Main Board (P12) -> Audio Board (U160) -> Main Board -> Audio Out (& RFModulator). A very simple chain.

I have swapped out the Audio Head (well I actually swapped out the entire tape deck unit) - No change - still a screeching/distorted audio on Audio Out and RF Out. Next, I swapped the Audio Board out - no change.

I then tried to swap the main board out and - maybe I messed something up - but that put the entire machine into error mode (error 37 - according to the front display on power up)

After much testing, it appears I caused some sort of damage to the Control Board (U20). At least one of the caps has blown - not sure if there is further damage to the control board.

Anyway, swapped the control board for a spare and back to square one. Unit functions, but this time sound is completely muted. THEN... after about 10 mins, the replacement control board fails and the machine goes into error mode 37 again.

I am now thinking there is some sort of power-surge to the control board (and maybe across the unit - which may explain the original issue of distorted and now muted sound).

I have replaced the majority of the electrolytic caps in the power board (P32).

My question for the V2000 community is : "Have you seen anything like this before and what do you suggest as next steps? "

I am not a service engineer and have been struggling with this machine for a couple of months now. Any advice would be greatly appreciated.

Rob