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| LC TDK PSU issues | |
| Posted by: techknight on 2018-04-22 15:16:45 not sure what "massa" is. that would sort of label what it is. But from a quick eyeball, its a +12V regulator. | |
| Posted by: marmotta on 2018-04-22 15:20:39 Massa is ground in Italian :-D I try with generic 12v regulator? Positive regulator I think... | |
| Posted by: marmotta on 2018-04-22 15:24:10 LM7812 is good? | |
| Posted by: techknight on 2018-04-22 15:26:34 Wrong pinout. | |
| Posted by: marmotta on 2018-04-22 15:28:28 Yes LM7812 have the gnd on center pin... | |
| Posted by: techknight on 2018-04-22 15:30:13 Now I am thinking it something else, it has +12V, a GND, but it also has +5v going into it. That is very strange for a regulator. I dont have a TDK supply handy to figure it out so thats about as far as I can go. | |
| Posted by: techknight on 2018-04-22 15:32:14 The more a stare at it, the more it looks like a dual diode. maybe a clamping network. | |
| Posted by: marmotta on 2018-04-22 15:50:46 Yes is strange... the circiut already have 2 rectifier diodes (on the heatsink) this psu need three diodes? Or is a thyristor? | |
| Posted by: powermax on 2018-04-22 16:03:52 The badcaps forum (what a funny name :beige: ) has a board dedicated to PSU troubleshooting and repair. You could ask there if they can identify that mysterious component. There are several people around there skilled in the art... | |
| Posted by: techknight on 2018-04-22 16:14:38 Ah, I remember that forum. I used to frequent there alot back in the day. | |
Posted by: marmotta on 2018-04-22 16:27:12The badcaps forum (what a funny name :beige: ) has a board dedicated to PSU troubleshooting and repair. You could ask there if they can identify that mysterious component. There are several people around there skilled in the art...Thanks for the link, but I think the best solution is to see another tdk 699-0153.... | |
Posted by: powermax on 2018-04-22 16:44:14Thanks for the link, but I think the best solution is to see another tdk 699-0153....Well, if you can get a replacement PSU of the same type for little money, go ahead! If not, it's worth trying to fix the existing one as I did with my old Astec PSU (still working after been fixed). BTW, a quick ebay search reveals a used TDK 699-0153 for 79,95 € + shipping from Germany to Italy. I bet the fix is cheaper... Another attractive option is to attach a modern PSU with compatible voltages and wattage... | |
Posted by: MOS8_030 on 2018-04-22 16:48:46The more a stare at it, the more it looks like a dual diode. maybe a clamping network.I agree. That PS is similar to the Sony PS in my HD20 SC I recently worked on. Here's an image of the corresponding components in the Sony PS. Also apparently unmarked.  | |
Posted by: marmotta on 2018-04-22 16:52:28I agree. That PS has very much the same layout & design as the Sony PS in my HD20 SC I recently worked on.On the pcb is marked as diode... you can shot a photo of the entire pcb? | |
| Posted by: powermax on 2018-04-22 16:54:24 Is it correct that this TDK PSU is more than 20 years old? If so, getting another old unit doesn't guarantee it won't fail, too... | |
Posted by: MOS8_030 on 2018-04-22 16:56:56On the pcb is marked as diode... you can shot a photo of the entire pcb?Here you go. The best photo I have. I already recapped & reassembled the PS.  | |
| Posted by: marmotta on 2018-04-22 16:58:50 Seems to be very different | |
Posted by: MOS8_030 on 2018-04-22 17:04:16Seems to be very differentYes, they are not exactly the same. My point was I agreed with Techknight's observation that your mystery component looks like a dual diode. | |
Posted by: powermax on 2018-04-22 17:24:35The more a stare at it, the more it looks like a dual diodeMaybe FEP16CT? | |
| Posted by: marmotta on 2018-04-22 17:30:37 The others two diodes is c82m and is marked on pcb as CR51 CR52, the lost component is IC55 (CR is used for the diodes on this pcb) | |
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