UK Vintage Radio Repair and Restoration Discussion Forum

UK Vintage Radio Repair and Restoration Discussion Forum (https://www.vintage-radio.net/forum/index.php)
-   Vintage Television and Video (https://www.vintage-radio.net/forum/forumdisplay.php?f=37)
-   -   Philips VR2022 tape speed slight unstable (https://www.vintage-radio.net/forum/showthread.php?t=128694)

whiskas 10th Aug 2016 3:19 pm

Philips VR2022 tape speed slight unstable
 
Hi chaps,

I just got myself a tidy looking Philips VR2022 - it has some audio warble when playing back, and occasional frame roll/frame sync error (picture held in wrong position) - seems to be a tape speed regulation issue of some sort?

Does anybody have any good clues what might be the cause? (incase its a common fault - thought I'd ask)

Thanks for any help,
Rob

John123 10th Aug 2016 7:47 pm

Re: Philips VR2022 tape speed slight unstable
 
Do the usual things first: Check the condition of the belts; check the pinch roller for pits, cracks or a glazed look; clean the entire tape path; clean the audio/ control head; clean the lower head drum assembly and check the tape isn't rubbing/ sticking to it.

whiskas 10th Aug 2016 8:54 pm

Re: Philips VR2022 tape speed slight unstable
 
Hi John
Thanks for your message - I forgot to mention that I've already done the following
1. carefully hoovered out all dust (I don't like working on dirty sets!)
2. cleaned the entire tape path all heads and pinch roller (which looks near new and has very good grip like a new one)
3. Checked all basic tape transport functions - all works fine except for the mild-moderate audio warble.

I'm hoping that someone has good knowledge of these sets and may know of a possible cause for this type of misfunction. Perhaps something in the motor control servos etc? Or the tracking system...?

allander 10th Aug 2016 9:34 pm

Re: Philips VR2022 tape speed slight unstable
 
Tape Deck Circlip Pliers I used to have a internal/external circlip remover/replacer (pliers) , very fine, ideal for just about any - particular Philips tape decks anything from such as Stella/Cossor valve and Philips 4407 bought strangely in a '£ Shop' as part of a VCR service tool kit . I've recently searched through CPC Farnells, Ebay, etc but all seem too large so jobs line-up. . Does anyone have contact details of a firm who might help supply please?
Rather urgent chaps and I'm sure of value to others.
Rog.

simpsons 10th Aug 2016 10:34 pm

Re: Philips VR2022 tape speed slight unstable
 
I have just successfully brought back to life a Philips video 2000 with the same problem. First clean the capstan shaft removing any oxide from the top and bottom of the shaft using a scraper. Second, using Isopropyl or similar such as video head cleaner clean the pinch roller. Should you take it off, using a thin blade to push the circlip out, you will need to use a similar tool to hold the centre spindle into place when re assembling. Third, being very careful not to damage the heads, clean the headrum using Isopropyl etc.dripped onto printer paper which you rotate the drum against. Then using a cotton bud dipped in the afore mentioned cleaner, clean audio and erase heads and tape path. All things being equal this will do the trick but note these machines are not HiFi. Chris

dj_fivos_sak 11th Aug 2016 2:57 pm

Re: Philips VR2022 tape speed slight unstable
 
I don't think this model has a belt driven capstan. I think it has direct drive motors for the capstan and reels. If the pinch roller isn't bad and the tape doesn't stick to anything, check if the capstan motor spins freely. To me, this sounds like a capstan servo lock problem. I will provide a link for the manual too.

http://freeservicemanuals.info/en/se...SETTERECORDER/

Fivos

whiskas 11th Aug 2016 4:02 pm

Re: Philips VR2022 tape speed slight unstable
 
Hi Fivos and others
Thank you for your reply - Yes, it's all direct drive in the VR2022 as far as I can see - no belts to be seen anywhere!
I think you may be onto something - about capstan servo lock. Also, I will see if it's possible to get the capstan motor out and check it thoroughly and clean the capstand guide pin as good as is possible. (easier to do when its out).
Does anyone know if these capstan motors can be easily disassembled to clean /lubricate as needed, or are they sealed / best left alone?

dj_fivos_sak 11th Aug 2016 7:02 pm

Re: Philips VR2022 tape speed slight unstable
 
Can you take a photo of the capstan shaft and motor? I have never seen any V2000 machine in person and I don't know much about this format. Is the audio head used for tracking/syncing purposes on this format like VHS or Betamax?

samjmann 11th Aug 2016 7:36 pm

Re: Philips VR2022 tape speed slight unstable
 
Hi all

These machines servo's work quite differently to VHS/Beta. The capstan servo is controlled by reading the 'Dynamic Track Following' tones that are recorded onto the tape. The video heads 'height' is then modulated to follow the track closely, and if there is a larger error another signal is then sent to the capstan motor to control its phase! These are seriously complicated decks, but I never had a duff capstan motor in the time I serviced them. Do all the basics as previously posted, by now of course the motor could probably benefit by a tiny spot of oil.

Take a look at the underside of the tape guides, these sometimes used to wear with fine ridges that meant the tape path had to fractionally adjusted to compensate. As the video heads wear, you'll find that recordings made at the end of a tape will suffer with loss of vertical sync on the monitor. This was caused by the head actuators on the upper drum losing sensitivity with use. Another clue to this was less than perfect FF/REW search during playback.

If you're really keen, Steve Beeching's book 'Video Cassette Recorders' explains the principles of operation of these machines. Philips were 'Simply Years Ahead' back then...

JM.;)

dj_fivos_sak 11th Aug 2016 8:38 pm

Re: Philips VR2022 tape speed slight unstable
 
Some Grundig machines didn't have DTF. How did they use to track the tapes?

samjmann 12th Aug 2016 12:19 pm

Re: Philips VR2022 tape speed slight unstable
 
From what I can remember (it's some 34 years ago!), certain Grundig machines did not have the head actuators. The 'output' from the DTF circuit was capstan phase only, so in effect it was auto-tracking from the 4 field DTF sequence, rather than a average FM output that's used on VHS/Beta.

I think that these Grundigs were budget models, the 2x4 super model was the one I saw the most of. This had the perfect search and pause.

Going back to the original post, I found both the Grundig and Philips machines quite sensitive to back tension problems. This could lead to a 'tapered' lead FM output waveform which causes poor field sync. On the Grundig there was even a modification issued to generate a artificial field sync pulse as the field sync pulse was weak when using pre-recorded tapes.

The back tension on the Philips is done by the supply reel motor gently 'pulling the tape' in the opposite direction, the tension arm position set the motor torque. There's no back tension band!


All times are GMT +1. The time now is 6:18 pm.

Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.