Pioneer SA 9800 Power Supply Board Help
- Thread starter SYK3S
- Start date
There is a difference between a miswired power supply that is primed to self destruct, and a power supply that has survived power up, is regulating correctly, and an amplifier that displeases a protect circuit enough to make it keep the speakers disconnected.
DBT will NOT protect against the current surge of a power supply self destructing, and using a variac to ramp the suspect power supply up MIGHT give some warning, BUT there are always strange effects when slowly powering something up.
And ALL those supplies key off the +52v supply.
It is a hell of a lot easier to double check everything for correct installation, than it is to tune up for maximum smoke.
post pictures, showing the fronts of the transistors, from above. Should be two or three angled shots that expose them all to scrutiny.
DBT will NOT protect against the current surge of a power supply self destructing, and using a variac to ramp the suspect power supply up MIGHT give some warning, BUT there are always strange effects when slowly powering something up.
And ALL those supplies key off the +52v supply.
It is a hell of a lot easier to double check everything for correct installation, than it is to tune up for maximum smoke.
post pictures, showing the fronts of the transistors, from above. Should be two or three angled shots that expose them all to scrutiny.
SYK3S
Active Member
ok guys repaired and fully rebuilt psu new caps transistors etc and just went for it and powered her up and it blew the two fuses on the psu board im tearing my hair apart i have checked everything could it be the o/p transistors maybe some of the eight might have failed MTF where are you 
stevieg330
Member
Dbt
Hi,
On my SA-9800, when I power it up on the DBT, the relay clicks in fine. I can also play music through it although there is a bit of hum. The meter is the only thing that doesn't work on it.
I strongly suggest that you make one up if you haven't already. Might save your fuses and possibly some other components next time
Check all the components you put in are the right way round. Hope that doesn't come across as condescending (it isn't meant to) but it's easily done when some of the new transistors may have different bce connections than the originals.
Hope this helps
Kind Regards
Steve
Hi,
On my SA-9800, when I power it up on the DBT, the relay clicks in fine. I can also play music through it although there is a bit of hum. The meter is the only thing that doesn't work on it.
I strongly suggest that you make one up if you haven't already. Might save your fuses and possibly some other components next time
Check all the components you put in are the right way round. Hope that doesn't come across as condescending (it isn't meant to) but it's easily done when some of the new transistors may have different bce connections than the originals.
Hope this helps
Kind Regards
Steve
Loddestuen
New Member
Old-thread-revival.. But that don't matter because the amp is much older. 
I'm overhaulin' two humming SA-9800 and the PSU boards that i have is AWR 196 B
There are a few more components to the list other than the list in post #2:
These are:
C17 = 10 uF 80V -> 10 uF 100V 647-UPW2A100MED
Q13 = 2SD712 -> 863-MJE15032G pnp to-220 55to300hfe 8mhz to-220
Q14 = 2SB682 -> 863-MJE15033G pnp to-220 55to300hfe 8mhz to-220
Cheers from Denmark
I'm overhaulin' two humming SA-9800 and the PSU boards that i have is AWR 196 B
There are a few more components to the list other than the list in post #2:
These are:
C17 = 10 uF 80V -> 10 uF 100V 647-UPW2A100MED
Q13 = 2SD712 -> 863-MJE15032G pnp to-220 55to300hfe 8mhz to-220
Q14 = 2SB682 -> 863-MJE15033G pnp to-220 55to300hfe 8mhz to-220
Cheers from Denmark
huskyfox
New Member
I'm surprised no one has mentioned anywhere that the collector and emitter are swapped on 512-KSC2690AYS (Q1, Q2) compared to 2sc1735 . Is this list just getting passed around in threads without much testing I wonder now? I'm sure the pinout is wrong for others too. Who's actually used these replacements and has feedback?
Exactly as Rick (rcs16) says, we spec electrical replacements, NOT functional duplicates (which probably no longer exist).
We EXHORT downloading data sheets and using them to determine correct transistor pinouts and guide the installation of each transistor.
These type of posts DO help, tho... we can see what parts of the message are getting lost in the rush, and try to compensate for that.
Between Mattsd and myself generating the lists, no less including larryderouin and zebulon1 (and quite a few others) , these lists have been used and tested multiple times.
And CONTINUE to behave because we damn well WILL get an angry callback if ANY of them misbehave.
In FACT, my lists were made SPECIFICALLY to stomp out those low probability brushfires that were "smouldering" in the engineering of the originals.
Been there, DONE that SO many times that the T-shirts are moth eaten.
A reasonable question, for someone who has not read many of the threads where the differences were EXPLICITLY called out in the instructions.
No less the discussions of the mental "rotation" techniques to figure out a transistor installation.
And CONTINUE to behave because we damn well WILL get an angry callback if ANY of them misbehave.
In FACT, my lists were made SPECIFICALLY to stomp out those low probability brushfires that were "smouldering" in the engineering of the originals.
Been there, DONE that SO many times that the T-shirts are moth eaten.
A reasonable question, for someone who has not read many of the threads where the differences were EXPLICITLY called out in the instructions.
No less the discussions of the mental "rotation" techniques to figure out a transistor installation.
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