it´s being a while since i was on this site , lots of projects in my house is taking all the time, but now it seems to be better.
For a month ago i got this oldie VHS, a real tank from 1981, it´s a rebadge JVC HR 7700 as you know, it was left in a barn on a farm for the last 15 years, but in okay condition, a little rusty but okay.
it was working in play af ff and rew, but over the night somthing happend, so i can´t turn it on, i found the fault som it now working again, but a new problem come, the issues is that it will only play few seconds and the go back in stop, same happens if i press FF and REW, only in pause and slow mode it will be in "play".
Does anyone in here in this great forum, have experience with those old bastards? i really wat it back to life again.
Sincerely alex 🙂
Hi Alex and nice to see you back. If in FF and play the takeup reel is turning ok and not spilling tape into the machine then you need to check the rotation sensor on the takeup reel.
The gap could be blocked or possibly the infra red LED may be failing and the output from the photo-transistor may be low in amplitude or missing. Which Mechacon version is fitted to your machine? Mine has the later type fitted with the smaller PCB, circuit attached
.
John.
Hi John.
Nice and great to be in here again 🙂
And thanx for your answer, that was also my opinion, because the "run" led on the left site didnt flash, unfortunally i can´t se the counter, only "clock" and channel number is present on the display, so one of the D552C IC display drivers is fauty.
i will check the sensor tommorow, the strange is was working before i change the servo board, but maybe the fault is on the "new" booard? i have to locate the circuit .
Sincerely Alex 🙂
Alex I would be very surprised if the display driver IC is faulty but if there is corrosion on the pins it could be possible. It's much more likely to be a faulty CF2 on the Tuner/Timer board just behind the power supply. Usually just resoldering the legs will restore temporary operation.
John.
Alex I would be very surprised if the display driver IC is faulty but if there is corrosion on the pins it could be possible. It's much more likely to be a faulty CF2 on the Tuner/Timer board just behind the power supply. Usually just resoldering the legs will restore temporary operation.
Thanx again John, i will make it a try,
you got right, on those two white plugs on the display board, was corroded, but how to i clean the plugs indside? i do it tomorrow, now it´s time to sleep, work is calling at 4.00 am :-O
Alex 🙂
Hi Alex, I can't take credit for guessing about corrosion on the plugs as I was thinking of the legs of the IC, I still think it's more likely to be the ceramic oscillator CF2 on the Tuner/Timer especially if it's a salmon pink or red colour type. I suspect corrosion on the plug would cause just some of the segments of the clock part of the display not to light up or cause uneven illumination.
If the corrosion is severe then if were me I would remove the pins, cut off the plugs and solder the leads directly to the board. Some very early machines were made like that.
4.00 am start, oh dear. I have trouble starting at 8.00 am ?
John.
Well so far so good, i found the fault why it stopped in FF/REW and Play, it was a defectice sensor under the left reel, it works fine for about 30 min, and then a new fault came, now it runs in FF and Rew, but if i press Play, it dosent load, and the head drum dont run.
Alex I would be very surprised if the display driver IC is faulty but if there is corrosion on the pins it could be possible. It's much more likely to be a faulty CF2 on the Tuner/Timer board just behind the power supply. Usually just resoldering the legs will restore temporary operation.
i toke a look on the CF2 board, end it looks like crap, a lot of bad soldering and corroded areas, so maybe thats the issue there? i have another board i kan try, but first i want it to load the tape again,
Alex 🙂
