Panasonic top-loader VCR Issues

[Electronic M]

The playback speed is not sensed with a switch. It's detected from the linear control track of the tape by the electronic circuits that control tracking.

Usually the only user speed control is for recording mode only.

If it's that old it's probably worth trying to fix even if it's a complex electronic issue, but a service manual with schematic is going to be critical to success.

[vortalexfan]

Originally Posted by Electronic M

The playback speed is not sensed with a switch. It's detected from the linear control track of the tape by the electronic circuits that control tracking.

Usually the only user speed control is for recording mode only.

If it's that old it's probably worth trying to fix even if it's a complex electronic issue, but a service manual with schematic is going to be critical to success.

I do have a couple of Service Manuals for this VCR, but they are Sam's Photofacts that I downloaded from their website, so the schematics and what not are cut up into pieces.
Could a bad capacitor in the control board cause these issues? I know this unit uses the old Matsushita caps that were notorious for failing over time (the purple ones.)

So what part of the service manual would I look under to find that circuit, so I can start troubleshoot it?
Is there a specific name for that portion of the VCR Circuit? I'm asking because the Service Manuals I have go by the names of what Panasonic put on each of the boards (ie Servo Board, etc.)

[vortalexfan]

OK, so I tried out an LP recorded tape in the VCR and that also had some trouble playing in the VCR, so apparently whatever circuitry is involved with the VCR reading the speed of the tape on the control track on the tapes must control the SP and LP together and SLP is controlled separately from the SP and LP modes.
Although LP mode even though it wasn't playing at the right speed it was a much clearer picture (not as much sync issues) as the SP mode had, in SP Mode the picture had terrible sync problems (vertical and horizontal hold issues.)

Also how common was it for a VCR to have a failure of the speed sensing control system? I'm asking because this is the first VCR I've worked on that had this issue out of about 30+ VCRs I've worked on in my nearly 20 years of working on VCRs for people or for myself.

[vortalexfan]

OK, so now I've replaced so far 42 capacitors in this VCR all of them of which had the green corrosion on the capacitor wire leads (the corrosion was on either one or both legs of the capacitors, but thankfully it wasn't bad enough to of eaten through the circuit board yet.)

I removed the Luminance and Chromanance board and replaced at least 2 dozen caps on that board alone (all of them had the green corrosion as well), and so far it seems that 99% of the capacitors I've replaced in this VCR were 47uF 16v capacitors with the other 1% being other values.