Hi.
I'm trying to repair a Hitachi VT-M922E(UK) VCR, a 2-head model, manual dat ed 1992. The previous owner said it had been in the loft for a few years.
On inserting a cassette, the tape is loaded around the heads, and the video head drum sounds like it's speeding up and slowing down rhythmically (alth ough the exact rhythm varies) with a cycle of just over one second, and is quite loud.
In play, I can sometimes see a rolling snap of the picture, although it's m ostly noise rolling up the screen in some sort of sync with the revving. I n-picture PAUSE, REV and CUE modes yield a normal, stable picture except fo r the usual bars of noise I expect from VHS. In those modes the head drum speed is stable and it's quiet. In the transition back to play the picture can be recognisably stable for 1-2 seconds before the revving and instabil ity return.
The machine goes through phases where, after operating for a while, engagin g and disengaging REV, CUE or PAUSE can sometimes leave it running stable, until I either stop and restart the tape, engage a special play mode other than the current 'magic' one, or briefly knock the top of drum with a piece of chamois leather on the top. Switch the machine off and come back to it the next day, and that 'magic mode' no longer works. The magic mode diffe rs each time - they're not interchangeable.
As far as audio is concerned when, when the head is revving... Connected through SCART or RF to my only remaining CRT TV, the audio is cho ppy (again in sync with the picture rolling and the revving). I connected it to a year-old LCD TV via SCART and the audio was completely stable even though the video was still rolling and the TV was blanking the screen thank s to all the noise.
I have tried the following: * cleaning out the dust from around the rear vents * repeated manual cleaning of all heads - although I've not done a manual cleaning of the video heads since remo ving the auto-cleaning roller which I understand could have been putting cr ud back onto them * removed the top drum, revealing a fairly fine blond hair stuck to the un derside of it (which I duely removed) * thinking perhaps the drum may have been sticking slightly, I applied a d rop of sewing machine oil in the bottom of the lower drum (I took the magne tic cap off the bottom, revealing the motor coils and the shaft that spins the upper head, and put a drop of the oil on the outside edge of that shaft and allowed it to drain in for a couple of minutes. I then swabbed up lef tover oil) * fiddling with the backtension lever during playback to see if I can brie fly eraidicate it - picture became slightly stronger with extra tension the re but revving and picture-rolling continued.
None of the above seem to have produced any noticeable improvements.
The Auto Tracking feature doesn't seem to be affected - the 'TRACKING' ligh t blinks for a while and becomes steady within half a minute. Adjusting th e tracking manually via remote doesn't help.
I have noticed also that in reverse modes, particularly REV search, the tap e seems to push up the A/C head and behind a hook, and make crinkling noise s. Unsure whether this is related, but either way I'd like to sort that ou t too!!
The machine also smells like something's getting quite warm. A heatsink in the PSU gets quite hot to the touch (no exact temperature readings, sorry) .
If anyone has any clues as to what's going wrong, or suggestions as to how I might fix any of the symptoms I've described, I'd appreciate your help.
Thanks,
Nick