Theoisle
Member
I've been working on this power supply for a while now and cannot figure why it won't start unless you turn it on and off several time or turn it on and leave it on for a while and then turn it off and then back on. I have checked components in and out of circuit and cannot find any anomalies. It runs perfect once started and you can turn it off and back on with no problem. It seems to need to "warm up" a bit and then it starts working when switched on. My main suspect is a black module that gets a startup voltage of about 9.5 volts from the mains and then gets boosted to about 18 volts with the switched mode transformer winding. I have tried to reheat the connections on the module with a hot air rework station and even scraped off some solder points to reheat with my solder iron. This is a Skynet SNP-200E power supply and the module is 900-250T-1.
When not starting I get no pulses out of the module. (no surprise there) When operating I get a nice clean pulse that varies in width with load. I can adjust the voltage output. It does not appear to be shutting down due to overvoltage. When powering up I monitored the module and it either gets pulses or none. This is the only problem now with this old 286. I would really like to get it running again. I have another the same as this. I hate to take it apart and swap that black module, but that may be the only way to isolate this. I can't find anything on this power supply anywhere.
Has anyone ever see this on this power supply or a similar one?
When not starting I get no pulses out of the module. (no surprise there) When operating I get a nice clean pulse that varies in width with load. I can adjust the voltage output. It does not appear to be shutting down due to overvoltage. When powering up I monitored the module and it either gets pulses or none. This is the only problem now with this old 286. I would really like to get it running again. I have another the same as this. I hate to take it apart and swap that black module, but that may be the only way to isolate this. I can't find anything on this power supply anywhere.
Has anyone ever see this on this power supply or a similar one?