Panasonic top-loader VCR Issues

[Electronic M]

Haven't dug that deep into a deck that old with that issue but if I wanted to figure out which board(s) are involved I'd trace the control track wiring off the stationary head (which also contains the linear audio head on most decks) to a board and also trace the head drum and capstan motor wiring to a board. Those boards are likely involved. The older the VCR the more spread out the circuitry the first models may have read the control track on one board and passed it to 2 separate servo boards, the most recent ones did everything in the entire deck on one board. How muchand what was on one board in early decks sometimes has more to do with how compact they could build it by putting things certain places than logical placement.

If there's block diagrams in your service literature that may help you find things too.

[vortalexfan]

Originally Posted by Electronic M

Haven't dug that deep into a deck that old with that issue but if I wanted to figure out which board(s) are involved I'd trace the control track wiring off the stationary head (which also contains the linear audio head on most decks) to a board and also trace the head drum and capstan motor wiring to a board. Those boards are likely involved. The older the VCR the more spread out the circuitry the first models may have read the control track on one board and passed it to 2 separate servo boards, the most recent ones did everything in the entire deck on one board. How muchand what was on one board in early decks sometimes has more to do with how compact they could build it by putting things certain places than logical placement.

If there's block diagrams in your service literature that may help you find things too.

OK, so I figured out that the control track reading is controlled by 2 boards in this VCR, the Audio Board and the Servo Board, and sure enough when I took those boards out and looked them over they had several electrolytic caps that had spewed their guts (the green corrosion on the wires coming out of the bottom of the capacitors.)

So when I replaced all of the ones that were visibly defective, then I put the VCR back together and sure enough it started playing LP recorded tapes properly, but its still not playing SP tapes properly yet.
So I'm going to have to go back over those boards again and see if there were some capacitors that I missed that weren't as obvious looking and replace those, and I think it will be good to go.

[vortalexfan]

Well I double checked the boards I worked on earlier and I found several more bad caps I missed, so I replaced those as well, and in total I replaced between the audio board and the Servo Board a whopping 13 capacitors which all suffered from the green corrosion on the capacitor leads, but unfortunately instead of making it better, it made it worse, somehow.

it will still play LP and SLP (EP) tapes just fine but when you try and play the LP and SP tapes instead of getting a picture, I just get video noise (the same kind of noise you get if a tape's tracking is severely off) except that the tracking isn't off the audio is just fine (in LP Mode) and in SP mode it still won't switch to the correct speed.

And I'm not sure what else to look for because I've replaced all of the bad capacitors in the Servo Board and the Audio Board, and it only restored operation to LP Mode, SP Mode is still not functioning, unless there's something else I'm missing?