Panasonic NV-L28B Repair - UK Vintage Radio Repair and Restoration Discussion Forum

Helicalscan · 28th Sep 2019, 6:30 pm

I Found the L-28 in a charity shop in (as advertised) good working order, however this turned out not to be the case, It didn't cost too much & I like to tinker. It did power up, but it would not accept a tape. no idea how long it had been sitting unused, but guessing quite a while.

So usual checks, starting with the psu, the 1uf 400v cap had been changed at some point but was duff again, capxcon 85c no surprise really! the rest were original and completely shot. Re capped the entire psu, still not accepting a tape.

Next I removed & cleaned the mode switch, it was badly tarnished. re fit, this time it did accept the tape & play started, hit stop then eject no problem... so I thought, within 2 seconds it pulled the tape back in by itself & play started again.

Left it over night, still doing the same ejecting then pulling the tape back in, it had been such a long time since I had worked on a Panasonic G deck, i forgot the loading mech has a mode switch of sorts to engage loading, this turned out to be as tarnished as the main mode switch, quick clean solved the problem, hooked it up to a tv via scart & was amazed by the picture it produced...that is until I tried a particular pre recorded tape with what i think is called macrovision copy protection.

It was making the top of the picture skew ever so slightly &flicker dark/light, it took me all day to remember this, but eventually it dawned on me

I recall Panasonic released a service bulletin many years ago, to remedy the skew symptom.
The L-28 is a digital VCR & has extra features accessed by the remote, these extra features need additional circuitry & this happens to be inside a metal box underneath the main PCB, the video is passed through this box regardless of any digital effect used or not, the cure is relatively simple, a 4.7uf 50v polarised cap across C66 or ref C9566 with the negative lead closest to the large IC (AN3182NFBP), The fiddly part is removing the foam pad which covers C66. I'll post some pics soon, when I work out how

Hope this helps. Apologies if the format is wrong or if its a tad vague, its been a while.

28th Sep 2019, 6:30 pm	#1
Helicalscan Diode Join Date: Aug 2017 Location: Leeds, West Yorkshire, UK. Posts: 2	Panasonic NV-L28B Repair I Found the L-28 in a charity shop in (as advertised) good working order, however this turned out not to be the case, It didn't cost too much & I like to tinker. It did power up, but it would not accept a tape. no idea how long it had been sitting unused, but guessing quite a while. So usual checks, starting with the psu, the 1uf 400v cap had been changed at some point but was duff again, capxcon 85c no surprise really! the rest were original and completely shot. Re capped the entire psu, still not accepting a tape. Next I removed & cleaned the mode switch, it was badly tarnished. re fit, this time it did accept the tape & play started, hit stop then eject no problem... so I thought, within 2 seconds it pulled the tape back in by itself & play started again. Left it over night, still doing the same ejecting then pulling the tape back in, it had been such a long time since I had worked on a Panasonic G deck, i forgot the loading mech has a mode switch of sorts to engage loading, this turned out to be as tarnished as the main mode switch, quick clean solved the problem, hooked it up to a tv via scart & was amazed by the picture it produced...that is until I tried a particular pre recorded tape with what i think is called macrovision copy protection. It was making the top of the picture skew ever so slightly &flicker dark/light, it took me all day to remember this, but eventually it dawned on me I recall Panasonic released a service bulletin many years ago, to remedy the skew symptom. The L-28 is a digital VCR & has extra features accessed by the remote, these extra features need additional circuitry & this happens to be inside a metal box underneath the main PCB, the video is passed through this box regardless of any digital effect used or not, the cure is relatively simple, a 4.7uf 50v polarised cap across C66 or ref C9566 with the negative lead closest to the large IC (AN3182NFBP), The fiddly part is removing the foam pad which covers C66. I'll post some pics soon, when I work out how Hope this helps. Apologies if the format is wrong or if its a tad vague, its been a while.