Can anyone point me to a replacement power transformer for a Heathkit W5M.
I'm not a tech, so any information on repair or replacement would be much appreciated.
Hate to see one of these become a doorstop.
I'm not a tech, so any information on repair or replacement would be much appreciated.
Hate to see one of these become a doorstop.
Those power transformers are potted and not repairable by a non-expert, and expensive. I would look for a replacement, but then it will be (most likely) unpotted. You will need to decide what you can live with.
You seem to be in Canada, so Hammond will likely be the most economical. Their offering doesn’t seem particularly close but could be made to work with some adjustment to the rectifier (5AR4 in stead of 5R4 might work). Being US-based I don’t know good places to buy Hammond transformers in Canada.
See: http://www.hammondmfg.com/pdf/EDB379X.pdf
I also checked the Edcor catalog and this one looks like a very good match:
EDCOR - XPWR077
Good luck!.
This would be the exact original transformer model and a great find, but only if the seller would be willing to guarantee its functionality. Suggest you contact the seller. Beware, though, the sellers stated “ I do not accept returns on used and old items”
Last edited:
What I suggest you do is to find a replacement that has the appropriate windings that you need and that will fit in a can.
Take your old can/transformer and hit it with a propane torch (the kind for driveways). It shouldn't be enough heat to melt the can, but it will burn out the old transformer. You can then take it to an abrasive blaster to have the can cleaned up, or use some elbow grease to get all the gunk off so you can install the new transformer. You'll want to do this away from people who will call the RCMP on you, as it will make a lot of nasty black smoke. Pay careful attention to how the transformer is oriented in the can, as you need to put the new one back into the can in the same orientation.
For the new transformer, you'll need to make a little piece of peg board that bolts to the can and has some 1/2" holes where the wires should come out so they will feed through the chassis holes where the transformer mounts.
To pot the transformer, do use actual potting resin. Pour a small layer into the can to give you a base to rest the power transformer on. When that cures, position the transformer in the can in the same orientation as the old one, thread the wires through your wire holder, then fill the rest of the can with the potting resin. I would recommend having a cool place to let the epoxy fire off, as it will get that can pretty hot.
Take your old can/transformer and hit it with a propane torch (the kind for driveways). It shouldn't be enough heat to melt the can, but it will burn out the old transformer. You can then take it to an abrasive blaster to have the can cleaned up, or use some elbow grease to get all the gunk off so you can install the new transformer. You'll want to do this away from people who will call the RCMP on you, as it will make a lot of nasty black smoke. Pay careful attention to how the transformer is oriented in the can, as you need to put the new one back into the can in the same orientation.
For the new transformer, you'll need to make a little piece of peg board that bolts to the can and has some 1/2" holes where the wires should come out so they will feed through the chassis holes where the transformer mounts.
To pot the transformer, do use actual potting resin. Pour a small layer into the can to give you a base to rest the power transformer on. When that cures, position the transformer in the can in the same orientation as the old one, thread the wires through your wire holder, then fill the rest of the can with the potting resin. I would recommend having a cool place to let the epoxy fire off, as it will get that can pretty hot.
Get a new equivalent transformer that is rated for 120VAC line.
The old ones were rated for 115VAC line, so the B+ will be too high now.
The old ones were rated for 115VAC line, so the B+ will be too high now.
54-32
As luck (?) would have it, just yesterday I found an old Heathkit bulletin that had specs for a handful of Heath amplifier power transformers, electrical and dimensional.
The purpose of the bulletin was to notify someone (maybe service personnel rather than customers, based on it being correspondence) of unavailability of a variety of Heath p/n power transformers. They recommended one transformer as a substitute for the entire list. PC8412...was that Stancor? (I have to look when I get home).
I was disappointed at how different they all were, but I guess it worked better than the failed transformer on hand!
It had higher current ratings but voltage was in the middle of the range the extinct ones spanned.
It notified the reader that new mounting holes would need to be drilled.
Well, that substitute is almost as scarce now.
I, too, would just chose what's currently made. Seems smarter in many ways.
I will gather that minimally-useful data for anyone who wishes to share it. It's mostly useless but for the specs of the original NLA transformers. NLA meant No Longer Available to Heath purchasing people. Not Like Anything works, too.
Murray
As luck (?) would have it, just yesterday I found an old Heathkit bulletin that had specs for a handful of Heath amplifier power transformers, electrical and dimensional.
The purpose of the bulletin was to notify someone (maybe service personnel rather than customers, based on it being correspondence) of unavailability of a variety of Heath p/n power transformers. They recommended one transformer as a substitute for the entire list. PC8412...was that Stancor? (I have to look when I get home).
I was disappointed at how different they all were, but I guess it worked better than the failed transformer on hand!
It had higher current ratings but voltage was in the middle of the range the extinct ones spanned.
It notified the reader that new mounting holes would need to be drilled.
Well, that substitute is almost as scarce now.
I, too, would just chose what's currently made. Seems smarter in many ways.
I will gather that minimally-useful data for anyone who wishes to share it. It's mostly useless but for the specs of the original NLA transformers. NLA meant No Longer Available to Heath purchasing people. Not Like Anything works, too.
Murray