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Hi guy's,
I'm not back from hiatus. I just have a question. On my days off, my “B” had a chassis go up in flames. I've never seen this before & I was wondering if anyone could tell me what caused what.
(82-70 - SS chassis - Omega-Tek MK- 70)
The chassis was completely rebuilt last month. It wasn't rebuilt due to a problem. I'm going thru all the chassis because they haven't been serviced by someone that knew what they were doing since they left the factory.
When I 1st tested the chassis, after the rebuild, the B.E. relay was sticking. I cleaned up the contacts but it didn't help, so I changed the relay.
It functioned fine for about 1½ days. Then, no B.E. motor run. (Everything else functioning normally) While my “B” was troubleshooting the problem (he had his face pretty much in the chassis), the 2 varistors on the heat sink assy & 2 disc capacitors on the MK-70 started to release their smoke, then caught fire. The 2 caps on the MK-70 that fried were the ones directly below the “cycle from desk” jumper. According to the PC board layout that comes with the installation instructions, they are “M3” & “M4”.
Every bit of solder on the heat sink assy melted – not just the solder at the varistors. All the power diodes on the heat sink assy check out OK with the meter. Nothing else in the chassis is visually bad or out of place.
The B.E. relay, which was the last thing that was messed with, checks out OK. It's wired properly & shows no obvious signs of overheating.
My question is… What precipitated the whole thing?
Did the varistors fry the MK-70? Did the MK-70 fry the varistors or was it something else that fried them both?
Thanks
[img]/content/btubb/images/%%GRAEMLIN_URL%%/usflag.jpg[/img]
I'm not back from hiatus. I just have a question. On my days off, my “B” had a chassis go up in flames. I've never seen this before & I was wondering if anyone could tell me what caused what.
(82-70 - SS chassis - Omega-Tek MK- 70)
The chassis was completely rebuilt last month. It wasn't rebuilt due to a problem. I'm going thru all the chassis because they haven't been serviced by someone that knew what they were doing since they left the factory.
When I 1st tested the chassis, after the rebuild, the B.E. relay was sticking. I cleaned up the contacts but it didn't help, so I changed the relay.
It functioned fine for about 1½ days. Then, no B.E. motor run. (Everything else functioning normally) While my “B” was troubleshooting the problem (he had his face pretty much in the chassis), the 2 varistors on the heat sink assy & 2 disc capacitors on the MK-70 started to release their smoke, then caught fire. The 2 caps on the MK-70 that fried were the ones directly below the “cycle from desk” jumper. According to the PC board layout that comes with the installation instructions, they are “M3” & “M4”.
Every bit of solder on the heat sink assy melted – not just the solder at the varistors. All the power diodes on the heat sink assy check out OK with the meter. Nothing else in the chassis is visually bad or out of place.
The B.E. relay, which was the last thing that was messed with, checks out OK. It's wired properly & shows no obvious signs of overheating.
My question is… What precipitated the whole thing?
Did the varistors fry the MK-70? Did the MK-70 fry the varistors or was it something else that fried them both?
Thanks
[img]/content/btubb/images/%%GRAEMLIN_URL%%/usflag.jpg[/img]
) left a punch sitting up by the chassis, during leagues, the machine vibration made it roll & fall into the wireway where there's no capping under the chassis, and shorted the TS strips.
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