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: PMD transistor MJ15004 MJ15004G abwdvm 07-17-2008, 06:33 PM I have 2 different Dtech PMD's. Took off the caps and found two different transistor part numbers. MJ15004 MJ15004G Anyone know the differences in the two? Does it matter? monel_funkawitz 07-17-2008, 07:09 PM They are the same, but the "G" is lead free. Both are PNP, 20 amp, 140v, 250w powerbase transistors. http://www.onsemi.com/pub_link/Collateral/MJ15003-D.PDF HamOP 07-17-2008, 07:34 PM Are these the usual failure point for the PMDs? These transistors are $3.29 each. Could be the PMDs are easily and cheaply repairable! Anyone have a dead PMD that I can play with? Mine's still working (Knock on wood). monel_funkawitz 07-17-2008, 11:26 PM This story has been hashed a thousand times in the past. They are sealed in potting compound. Can they be fixed? Possibly, but it is far from easy. Spend your time on something creative, like basket weaving. HamOP 07-18-2008, 05:59 AM Spend your time on something creative, like basket weaving. I was almost kicked out of the 5th grade over basket weaving - Really - My mom kept that 1/2 a finished basket for years. If the transistors are the failure point it seems that removing the top of the transistor would let one get to its connection points, even if the transistor can't be removed. Remote a few new ones and away you go. This would also get the heat away from the control electronics. I'd like to try it... I spent 40 years fixing electronic stuff and kind of miss it -- Don't miss going somewhere to do it though :-) FWIW - A few years ago my ham station took a lightning hit. Everything was working again a week later. VERY busy week for me. So again: Got a bad PMD? I'll take it... Just let me know how much for shipping and handling. chevylover 07-18-2008, 06:35 AM Sounds interesting. Try and let us know the results ! Cu, Sven Missy Good Wench 07-18-2008, 10:40 AM For the low cost of a new Dtech I would not waste my time screwing around with replacing the transistors. I have been hung out to dry more than once with a bad PMD and anymore carry a spare even though I have a new remote mounted Dtech on my truck. Best MGW JMJNet 07-18-2008, 10:51 AM The last time somebody wants to reverse engineer it, he or she was never heard of again!!! Like the black hole was getting to them or something. This happen in this forum and the other forum, too. jifaire 07-18-2008, 11:36 AM For the low cost of a new Dtech I would not waste my time screwing around with replacing the transistors. I have been hung out to dry more than once with a bad PMD and anymore carry a spare even though I have a new remote mounted Dtech on my truck. Best MGW See, that's why I bought me a Heath PMD Isolator in the first place. 7-yr warranty, only rumours of a failure or two out of the thousands sold and installed... mine has been working hard for 4 yrs and 100,000 km. Still got 3 years of warranty left; that's a lot of trailer-pulling! Matt Bachand 07-18-2008, 07:20 PM See, that's why I bought me a Heath PMD Isolator in the first place. 7-yr warranty, only rumours of a failure or two out of the thousands sold and installed... mine has been working hard for 4 yrs and 100,000 km. Still got 3 years of warranty left; that's a lot of trailer-pulling! Same here about Heath unit.... even submerged it in a huge puddle of frozen water / slush... Talk about thermal shock... No problems then, or ever. | ||