| Electronics > Repair |
| Mastech HY5020E 50v 20a Bench Supply: Economical to repair? |
| (1/13) > >> |
| richfiles:
So, I was given a blown 50 volt 20 amp single output bench power supply. It's a "Mastech" HY5020E. opening it up, I can see that multiple parts have violently blown. The main board appears to be single sided, and I've not delved further into it to see how bad or how far charing reaches. The fuse on the rear is NOT blown, and I don't know if it was replaced or not after the initial magic smoke release. I have not attempted to power it up yet either. If I can find service information, my question is, is this economical to repair? Obviously, if it's just a selection of transistors, diodes, resistors and capacitors blown, then maybe cleaning it up, rebuilding any vaporized traces, and replacing the bad parts might be worth while. 50 volts at 20 Amps isn't anything to scoff at, especially for a hobbyist on a budget. It's far overkill for anything I can think of doing, but if I could get it up and running again, it'd definitely be a nice supply... Also, the excuse of anything I can think of doing does not eliminate further proofing my shop. If this level of damage is going to take a large investment though, I'd be better off putting it toward a dual tracking supply, which I'd find far more useful. I have a pair of Tektronix dual tracking supplies in a 500 series enclosure, but those are current limited to 400 mA, and I've already been held back by that no less than 4 times just this month! I need more power! ;D So, seeing the multiple violently blown parts... Salvage parts or repair? What's more economical? I must also say I was surprised at how small the toroidal transformer was, and theres'a a rectangular one as well. Am I possibly looking at a switching supply, vs a linear? Again, I've literally only popped the 4 cover screws, and not gone any further yet, so this is all pretty preliminary. |
| SeanB:
Switch mode power supplt, and with the whole input side and power devices very well crisped. Repairable so long as you replace everything, resistors, transistors, diodes and capacitors, and get the charred board clean. Especially those Samwha input capacitors, looks like they dumped themselves on the board and ripple did the rest. Probably best to replace with better ones, and the output side as well. |
| richfiles:
Replacing capacitors? No such thing as buying cheapie crapola caps! :-DD If I buy a replacement, I buy the rated value, and then limit search terms by manufacturer and highest available temp rating! ;D Yeah, I figured it'd be a full rebuild. I'm curious if anyone's done a rebuild like this before, can mayby throw me a guestimate at what I'd be in for. Fortunately, Mastech's website specifically says that if you want a schematic, just email them and they'll send you a PDF of your model. Nice! More manufacturers need to do this! :-+ |
| richfiles:
Well, got the schematic. We'll see if I can figure it out then. |
| Shock:
I'd say max about $15-$30 in components and about 3 hours work for a proper job removing the pcb, components, scrubbing and rinsing, testing for shorts and other components, identifying the parts and ordering them, soldering them in, testing and assembly. Any consumables you don't have on top of that. Even the dirtiest unethical repair with components on hand would be about 30mins. Of course if you don't know what your doing it could take longer and get you electrocuted. |
| Navigation |
| Message Index |
| Next page |