Home |
Search |
Today's Posts |
|
Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
|
LinkBack | Thread Tools | Display Modes |
#1
Posted to sci.electronics.repair
|
|||
|
|||
This hitachi P.S. is driving me nuts!
I've posted this before, but now I have some more info.
Here it is hitachi scope V1060 power supply: http://img.photobucket.com/albums/v338/gamow/PS.gif Seems pretty simple? What it does, It runs fine under reduced load, ie I put 22ohms resistor in series with the rest of the load on 55v circuit. As is it will produce voltages 40% lower than specs. To remove any doubt I disconnected all the loads and replaced them with resistors. To simmulate full load I've used : 11 ohms on 5V rail~.45A 22 ohms on12V rail~.37A 230 ohms on 55V rail~.2A It manages to output 43V on 55V circuit , all others respectively lower too .. Yes I've replaced all the capacitors on the primary side, actually I put 47m instead of 39 and 100 instead of 56 Still no change. Desoldered all the secondary diodes , They all check fine. Checked for the ripple on the secondaries (bad caps?) all in order. Bgin to suspect transformer itself. HERE I REALLY NEED HELP. Before try to rewind the transformer , can somebody with more experience than me look up the following waveforms? The first one was taken with all secondary windings disconnected(I've removed the diodes) The second with diodes soldered back and above mentioned resistive load reatached. Both were taken with a scope respecive to negative of line side capacitors(used isolation transformer ). At point 5 (primary winding) Here they go: No load: http://img.photobucket.com/albums/v3...ad-cropped.gif Loadded: http://img.photobucket.com/albums/v3...ded-croped.gif Help me please. Thanks. |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
wall oven driving me nuts. | Home Repair | |||
driving me nuts: shellac article/photos? | Woodworking | |||
ICs for Sale - Specials, obsolete and Memory | Electronics Repair | |||
ICs for Sale - Specials, obsolete and Memory | Electronics Repair | |||
ATT; Hobbyists and Repairmen I have accumulated a room of ICS, Transistors, Diodes , Mem Chips , Proms etc | Electronics Repair |