Look at the sweetness I received today...lol...WOW... somebody did a real hack job here??
P/S gate resistors burned
P/S drivers shorted
P/S fets missing and a few attempted to be replaced with gobs of solder
Output have clipped and re-soldered legs
Missing and burned source resistors
Gonna start on this soon, probably wont get lucky with and easy repair on this one from what I see in the output section.
I will keep things posted up on progress!!!
Wish me luck!!!
P/S gate resistors burned
P/S drivers shorted
P/S fets missing and a few attempted to be replaced with gobs of solder
Output have clipped and re-soldered legs
Missing and burned source resistors
Gonna start on this soon, probably wont get lucky with and easy repair on this one from what I see in the output section.
I will keep things posted up on progress!!!
Wish me luck!!!
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Some people should just not attempt to do repairs I guess, this one will be time consuming. HHHMMMM!!!
I have a power 1000a2 on the way from the same seller now I am a little nervous.
I have a power 1000a2 on the way from the same seller now I am a little nervous.
At least they're not coming back from buyers.
This one is likely to have protection circuit problems. It appears that at least one of the source resistors have failed.
This one is likely to have protection circuit problems. It appears that at least one of the source resistors have failed.
This is a good point, I have not had a come back yet, not to say I wont but not yet. I picked these 2 up off of ebay, seller ended auction early for my offer. 4 of the source resistors were burned open.
Ill trade you repairs lol yiour 800a2 for this 750x that i cant figure out
Atleast you didnt get it in with regulators from radioshack in the power supply fet locations ..
Atleast you didnt get it in with regulators from radioshack in the power supply fet locations ..
WOW I didnt know that.....ha ha lol..... I had a power 800.4 a tried several months back that Perry was helping me with and I finally gave up. I just could not get the voltage off of the channel or the bias to set. I changed everything in the whole channel.
I just couldnt figure it out......so its gonna be a sweet parts board now......LOL!!!
I do have a perfectly working power 750X if you need any references let me know be happy to provide you with any info you need!!!
I just couldnt figure it out......so its gonna be a sweet parts board now......LOL!!!
I do have a perfectly working power 750X if you need any references let me know be happy to provide you with any info you need!!!
i havent worked on many of the older models. where u get those boards from to mount the transistors on? i seen some so badly damaged i kinda stayed away from them.
They are not really available anymore, I aquired a bunch lol and I have probably a 100 or so parts boards. If you ever need any I cant gaurantee I will have it but good chance.
The only time you ever really see them messed up is if someone has tried to pry the fets off and ripped the solder pad off or they have overheated it and the ruined the solder pad. If the MESHA board pad is loose or missing it is garbage.....you can cut and patch but it looks horrible.
I have just removed them on several Rockford amps and used Kapton tape and clamps and screws like the old DSM amps used. Alot of the DSM clamps will lign up with the holes in the newer amps (2003 and older newer). The MESHA board is not a must for the amp to function.
The only time you ever really see them messed up is if someone has tried to pry the fets off and ripped the solder pad off or they have overheated it and the ruined the solder pad. If the MESHA board pad is loose or missing it is garbage.....you can cut and patch but it looks horrible.
I have just removed them on several Rockford amps and used Kapton tape and clamps and screws like the old DSM amps used. Alot of the DSM clamps will lign up with the holes in the newer amps (2003 and older newer). The MESHA board is not a must for the amp to function.
OK powered up the supply and it powers up for 3 seconds then starts pulsing up to 40 amps current draw then to zero over and over?
Bias pots are all the way down, source resistors and output fets are removed from defective channel.
Could something in the protection circuit from the faulty channel cause this or do I have more issues in the supply?
Should I remove the rectifiers and try to power again?
I have a nice square wave on all of the gate legs of the power supply fets.
Bias pots are all the way down, source resistors and output fets are removed from defective channel.
Could something in the protection circuit from the faulty channel cause this or do I have more issues in the supply?
Should I remove the rectifiers and try to power again?
I have a nice square wave on all of the gate legs of the power supply fets.
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Are the power supply FETs heating evenly?
Is the board conductive where it's blackened next to the capacitor?
Is the board conductive where it's blackened next to the capacitor?
The board does not seem conductive, the p/s fets dont seem to be heating at all but I am only powering it for 5 seconds at a time.
Try twisting the transformer to see if it makes a difference in the current draw.
Do you see it trying to produce a square wave on the drains of the FETs or does the drain remain very near 12v and straight DC?
Do you see it trying to produce a square wave on the drains of the FETs or does the drain remain very near 12v and straight DC?
Ignore post 19 then.
Do you see the same DC voltage across each of the source resistors in that channel? Or is one higher and one lower than the others?
Do you see the same DC voltage across each of the source resistors in that channel? Or is one higher and one lower than the others?
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