Hey guys. I am working on the rectifier board in my EBD.

I have the repair kit from Big Baddy and have replaced the fuse clips, ceramic resistors, two burned out fuse clips, and the four big diodes.

A couple of questions:

1) the small diodes and resistor all look good. Should I bother with replacing them.

2) br1 was missing on the board. Br2 looks good. It looks like there is a pad of some kind mounted under br2 between it and the board. I assume it’s a spacer so br2 will touch the metal plate.

I’m at a bit of a loss on what do do with the rectifiers. The replacement ones are smaller and come with one heat sink for br1. How do I mount br1 and its heat sink. They originally install from underneath but I can’t see how they it will fit under the board with a heat sink. If I mount from the top the offset legs don’t match and you are changing where the leads go? I might just leave br2. If I replace it do I have to mount it off the board far enough so it contacts the metal plate to act as a heat sink.

Perhaps if anyone has a picture of how you did your board it would be helpful.

Sometimes the small simple things stop you and make you go hmmmm..

Thanks

Dave

Thanks for the advice guys.

I tested R3 and it measures 98.6k ohms which is in spec for the 100k. The diodes measured fine also.

I left br2 as is. With br1 I spaced it out temporarily to give it the right distance from the board and soldered it in. It will sit flush with the plate coplanor with br2.

Question. I have been working ems forever and am doing ok with the ss schematics and the like but then things come along and puzzle me. I always use the mm to check my work, mostly to ensure continuity as a cross check of the solder work and the check for shorts.

Schematics tell me br1 + leg goes to tp1 then on to three connectors on j3 and j1. Between the minus and + legs is the 25ohm ceramic resistor r2.

Continuity (beep) test says I’m good between + leg and tp1 j3 and j1 and it shows almost no resistance. . That aligns with the schematic. Same for + leg and one legs of the resistor. To the other leg of the resistor goes to ground i read 24.9ohms. These all beep out indicating continuity and that’s what I don’t get. With the mm set to ohms I read 24.9 ohms.

By this reading I am being told that I have continuity from the + leg to ground (through the resistor?). Is that right. Is that because with the beep test the 25ohms reads too low and is seen as continuous. I wouldn’t expect to see the + leg shorted to ground (with 25 ohms of resistance only).

I do see with br2 the wiring is the same but don’t get the same beep continuity. That one goes through 600 ohms though and I get a reading of 598 ohms.

Does this seem normal. I just want to make sure that something isn’t shorted that shouldn’t be.

Thanks

Dave

Thanks Jeff. Since I don’t truly understand electrical engineering I see 25ohms as a short because the meter beeps . Like you said those are probably thresholds in the meter. It’s nothing special but a decent fluke.

I have a small amount of grease that came with the rectifier. I hope it’s enough for both.

Dave

Thank you for the excellent info Quench.

I have a couple of pieces of the brown bakelite? board from an old em machine Will that do?

Dave

Thanks Quench.

I will follow your advice.

Dave