Low-usage Panasonic AG-MD835 with minor black streaking
 

Hi all,
I had a customer donate me a Panasonic AG-MD835 medical S-VHS VCR with a low drum hour count of about 30 hours with original head drum intact and has not been switched on for over a decade. It required some re-timing on the mechanism but now it can play tapes. There is minor black streaking/comets on extreme luminance transitions (so far in VHS mode) like small text but not always as it depends on the content. The test tapes are known to be good. Being a portable recorder, SMD electrolytics are everywhere, so that would be some cap-hunting. Anyone have experience with this model?

I know these medical VCRs are rebrands of the industrial broadcast models. Is there a known equivalent in the broadcast field for this VCR and what kind of TBC does this one use? Thanks in advance.

The TBC in the AG-MD-835 are not as good as the big Panasonic AG 7650 or 7750th

Capacitors I have no change.
Elko patients here are the last Pana AG 8600 + 8700

Manual cut-side 4 to 15

I have about 5 AG-MD835 with 9 H .......1500 H
but can not speak English.

Hi Goldwingfahrer,
Thanks for the info. Do any of your AG-MD835 units have black comets/streaks during playback of tapes recorded on consumer VCRs?

I expected the typical line TBC because the dropouts were compensated line by line. This is probably the last of the industrial VCRs in my area and it was free so better make the most of it. I hope to put up some image captures of it in action by the end of this week. As I don't have the exact service manual for this (I have the AG-MD830 manual which has circuit layout differences), it'll be some guess work for identifying the bad caps.

I thought black streaks around luma spikes = bad video head, not electrical issues.

No

Pana AG MD 835 Line TBC.. No.... = Full Frame TBC
I give the signal from the MD-835 to a Data Video DAC 7 [SDI-out] in the PC = = resultat properly.
I have about 4 Pana AG-MD-835 and about 2 AG-MD 830th
AG-MD-830 do not have full-frame TBC
and no line-TBC.

The Pana AG-MD-830 I have to connect to the Canopus NX.
The Canopus NX has a full-frame TBC.

I have the Pana AG-MD only PAL models

Honestly, medical VCRs were limited in ability, made for recording and NOT playback, were (ab)used heavily, and were in generally nasty conditions. I would not get anywhere near one, even if free.