Hey guys, First time poster.
I picked up a Soundstream Reference 405 a while back, it has sat on my shelf a good three years. I've tried to power it up and it keeps blowing both 20a fuses.
There's a lot of posts here on diyaudio regarding this issue and i've been through all of them and narrowed my issue to the 6x SMP50N60-25 power supply transistors.
I have also checked the TIP102 and TIP107 which are fine.
There's 4x FED16BT and 2x FED16DT rectifiers which i believe are testing fine (0.490v with + to pin 1 and - to pin 3).
At the end of the chain there is a LM340T15 and LM7915CT voltage regulators. I was hoping someone might have a schematic of this amplifier so i can confirm these are the correct components as i have a feeling this amp has been repaired once before.
Thanks in advance for your help!
Dan
I picked up a Soundstream Reference 405 a while back, it has sat on my shelf a good three years. I've tried to power it up and it keeps blowing both 20a fuses.
There's a lot of posts here on diyaudio regarding this issue and i've been through all of them and narrowed my issue to the 6x SMP50N60-25 power supply transistors.
I have also checked the TIP102 and TIP107 which are fine.
There's 4x FED16BT and 2x FED16DT rectifiers which i believe are testing fine (0.490v with + to pin 1 and - to pin 3).
At the end of the chain there is a LM340T15 and LM7915CT voltage regulators. I was hoping someone might have a schematic of this amplifier so i can confirm these are the correct components as i have a feeling this amp has been repaired once before.
Thanks in advance for your help!
Dan
Attachments
The lm340 number was a a date or lot code . If you look below that number it’s an 7815 regulator and yes it appears all components in your pictures are the correct part numbers .
Ref 405
Remove the power supply FETs and check that you have square wave pulses at each gate terminal.
Email me at ssm@zedaudiocorp.com and I shall send you the schems.
Please note all I am happy to help a person out but I know that there will be many requests for me to email schematics. I cannot spend the time to sit and send emails...sorry.
Remove the power supply FETs and check that you have square wave pulses at each gate terminal.
Email me at ssm@zedaudiocorp.com and I shall send you the schems.
Please note all I am happy to help a person out but I know that there will be many requests for me to email schematics. I cannot spend the time to sit and send emails...sorry.
Shorted transformers and shorted rectifiers are the most common problems for the power supply.
Did you check every output transistor?
See attached.
Did you check every output transistor?
See attached.
Thanks, Perry!
Yeah, the only ones i can find that have a short are the 6x near the transformer (SMP50N60-25)
I tested them with the multimeter set to diode mode, Positive lead on the drain and negative on source and have continuity.
Dan
The term continuity isn't good to use since it's vague.
When testing FETs, you can have something other than an open circuit if the gate is charged. The gate should always read open on ohms to the other two legs, any other reading means that the FET has failed. The other two legs will check like a diode (on diode-check) if the gate is discharged.
I thought that you had a problem other than shorted FETs. That's why I mentioned the transformer and rectifiers.
When testing FETs, you can have something other than an open circuit if the gate is charged. The gate should always read open on ohms to the other two legs, any other reading means that the FET has failed. The other two legs will check like a diode (on diode-check) if the gate is discharged.
I thought that you had a problem other than shorted FETs. That's why I mentioned the transformer and rectifiers.
ahh, i understand. In diode mode with positive on drain and negative on source the reading starts at 300 and keeps climing past 1000.
I tested in ohms with positive on the gate and negative on the other 2 legs and seeing open line? does that mean these fets are fine just not discharged?
Appreciate your help!
I tested in ohms with positive on the gate and negative on the other 2 legs and seeing open line? does that mean these fets are fine just not discharged?
Appreciate your help!
Have confirmed the 6x output fets are not the issue, i'm turning my attention to the rectifiers FED16BT.
Anyone have any advice on testing these with a multimeter?
Cheers
Dan
Anyone have any advice on testing these with a multimeter?
Cheers
Dan
I had a heck of a time finding doubler diodes for my REF500 when they went bad, hope yours aren't shot.
No solid (legit) suppliers that I've found, I got lucky and asked around to my electronics buddies who still had a bag of them so I saved them for a rainy day. They turn up on the bay from time to time, but I know how you feel about that.
If someone still has contact information for Jaime (SS parts on ebay), maybe they could check to see if he has any.
As a last resort, there other doublers that are readily available but they are reversed. You'd have to hardwire the output terminals to the correct board locations.
As a last resort, there other doublers that are readily available but they are reversed. You'd have to hardwire the output terminals to the correct board locations.