After re-soldering the eyelites & running fine for 6 months or so, My TT-101 has started having same issues with the stop button. Did you come to a fix for it?
JVC TT-101 Won't Stop
The Stop button on my recently purchased QL-10 doesn't work. It worked at first after the TT warmed up, but then quit completely. I since have replaced all 37 electrolytic caps on 3 boards, but it made no difference. The power voltages are correct. The button itself is fine and shorts pins 6 and 9 of the P8 connector on the main board, but the motor doesn't stop. What could be wrong? Any particular transistor or adjustment? Please help! -Alex
Showing 13 responses by gary7
Got back with Dave Brown at
modularsynthesis.
These are his thoughts. Dave Brown, Dec 23, 11:52 PM It’s been a while since I have looked at the schematics and I was looking for something in common between all of those. My gut reaction is a connector. Tin corrodes and becomes intermittent. I’ve also seen failures mostly on the single sided phenolic boards but without plating it would happen on this board also. On a normal PCB with plating, the connector pins are held firmly to the board. Without plating they are only held on by the rear pads since you can’t solder the front pads since the connector covers them. You can never get the connector absolutely tight to the PCB and the leverage of the pins will rock them. The runs fracture right along the connection to the soldering. It would exhibit the kind of behavior you are seeing and is exasperated by temperature differences.
What I do for repairs is use epoxy to glue the connector to the topside of the PCB and on the bottom scrape away the solder mask about 3/15” from the pad and jumper the connector pin over to the fresh copper.
Typically you can see the connectors move a bit when you rock them.
This makes more sense than a random trace crack or a cold solder joint in that there is constant stress on the pins with the cable tension.
The connectors going to the front panel PCB makes the most sense. I think there is a front panel PCB. It’s been a while.
Dave |
Well, trying to decide what to do with my TT-101, I pulled it out to have another go at the eyelets. I especially paid attention to the ones around the VR646 & VR647 pots that adjust the quick stop. Put it back together and ran for several hours testing the stop button in both 33 & 45. Seems to be fine, for now. It actually is stopping better. Before the platter had some drift after I hit the stop button. Maybe.....for now. https://www.youtube.com/watch?v=wIhIO7uoPY4 |
Oh, I'm very happy this worked. My thinking is that one or more of the eyelets that involves the stop sequence from the 1st solder go-round did not get a good dose of solder and it finally started having intermittent control issues. The platter drift before was not too terrible, but now it comes to almost a dead stop. Very happy indeed. |
best-groove ahhh ook no problems; but this then? It remains locked means that is that improvement? https://www.youtube.com/watch?v=-Rqmmcms1Tc Not sure what the improved version is. But it does start different than mine when he powered it on and pressed the 33 play button. The decimal point LED blinks several times when it powered on and then counted up to lock on 33.33 and stayed there. Wonder if it was a design change. |
Hard to get a good pics as the eyelets are small, silver bumps of solder. Some you really have to hunt for. If not mistaken, the SM on vinylengine has a schematic of the board that shown the eyelets connecting points in dark grey, you can use it to map them out. https://www.facebook.com/photo.php?fbid=2270251446319444&set=a.185305328147410&type=3&th... |