lopezluna
Active Member
Ok I will definitely mark and remove the output transistors
Pioneer sx-1050 no voltage at output caps problem
- Thread starter lopezluna
- Start date
lopezluna
Active Member
All you guys are great. I appreciate all you guys.a man with a 1050 to the rescue
lopezluna
Active Member
Ok it is where I though it was. Thanks merlynski
lopezluna
Active Member
@merlynski power supply awr-104 powered on with DBT
pin 2= .341v ac pin 4= .384v ac. Not good Im sure. Transformer bad maybe? I checked 10A fuse for continuity and all other fuses on awr-104 board. All had continuity.
pin 2= .341v ac pin 4= .384v ac. Not good Im sure. Transformer bad maybe? I checked 10A fuse for continuity and all other fuses on awr-104 board. All had continuity.
lopezluna
Active Member
Good morning fellas. Last night I took voltage readings of pins 2 and 4 on power supply board awr-104 and the readings were not good. Not even 1dc V on either. Does this mean my transformer is bad? Mine is the U.S model with the att-266 transformer. Anyone know if a att-290 multy voltage transformer will be a suitable replacement? Thanks guys
merlynski
Curmudgeon Electronicist
Unplug the unit from the wall/DBT. Set your meter on the Ohms range. turn on the power switch. Measure across the power plug for resistance. Should be a low resistance, more than 5Ω but not an open circuit.
If you have an open circuit measure resistance from pin 4 to pin 5 of the Surge Killer PCB AWX-098. On later models Pioneer used a different board AWX-108, but it does the same job, same pins. Should measure about 3.3Ω or slightly more.
This is the AWX-098:
This is the AWX-108:
It is next to one of the big main filter caps.
If it is open between pins 4 and 5 measure resistance across the thermal fuse, it should be 0Ω. If it is open you have a bad fuse. Replacements are available.
If you have an open circuit measure resistance from pin 4 to pin 5 of the Surge Killer PCB AWX-098. On later models Pioneer used a different board AWX-108, but it does the same job, same pins. Should measure about 3.3Ω or slightly more.
This is the AWX-098:
This is the AWX-108:
It is next to one of the big main filter caps.
If it is open between pins 4 and 5 measure resistance across the thermal fuse, it should be 0Ω. If it is open you have a bad fuse. Replacements are available.
lopezluna
Active Member
Ok will test as you instructed this evening when I get home. Thanks for the guidance, I do appreciate it
lopezluna
Active Member
@merlynski Hi, here are my readings
Power plug unplugged & switched On = 4.5ohms
PCB AWX-098 pin 4 to pin 5= 3.4ohms
Thermal fuse= 1.793ohms after it stabilizes. Hope this helps. Thanks, Ben
Power plug unplugged & switched On = 4.5ohms
PCB AWX-098 pin 4 to pin 5= 3.4ohms
Thermal fuse= 1.793ohms after it stabilizes. Hope this helps. Thanks, Ben
lopezluna
Active Member
@rcs16 Good morning. I read in a thread about a sx1250 needing a transformer and you mentioned the option of a att-291 the multy volt transformer was a option for him. Now if my transformer is indeed bad can I use the att-290 multy voltage transformer as a replacement for my U.S version transformer on my pioneer sx-1050? I see one listed and just want to keep my options open in case my transformer is indeed bad. Thanks rcs16, Ben
merlynski
Curmudgeon Electronicist
The Primary side of your transformer appears to be good.
Still unplugged, measure resistance from pin 2 to pin 4 on the AWR-104 Power supply PCB. Then measure resistance from each of those pins to the chassis ground.
lopezluna
Active Member
@merlynski here are my readings in awr-104 pcb
Pin 2 to Pin 4= 3.413 m ohm
Pin 2 to chassis ground = OL
Pin 4 to chassis ground = OL
Pin 2 to Pin 4= 3.413 m ohm
Pin 2 to chassis ground = OL
Pin 4 to chassis ground = OL
lopezluna
Active Member
@merlynski I went ahead and marked and removed all the output transistors. Should I put the heatsink back on the chassis and plug in the connectors or just leave it out? Thanks
merlynski
Curmudgeon Electronicist
Is that m mean Meg ohms? What range is your meter set to?
Verify the white wire from the transformer is connected to the star ground strap.
With the transistors removed there is no reason to reconnect/reinstall the heatsink at this time.
petehall347
the brandy coffee man
your transformer appears bad but very oddly .. maybe 2 broken wires .
lopezluna
Active Member
Meter is set to on Auto Range. White transformer wire is attached to star ground strap.
merlynski
Curmudgeon Electronicist
That says the main secondary winding for the transformer is open. Disconnect the red wires from the pins, or unsolder the red wire pins from the AWR-104 and measure resistance again just to confirm. There is something odd here. I would have expected an open in the winding to still have a connection from one side or the other to the (white) centertap.
Transformers are usually pretty tough, and can handle short term overloads quite well. Has this one ever been overheated that you know of?
Transformers are usually pretty tough, and can handle short term overloads quite well. Has this one ever been overheated that you know of?
lopezluna
Active Member
I have no knowledge of this receivers past history, I just purchased it on the bay site and contacted the seller that it was not as described at all. Got half refund back. I will go and remove red wires from pins and take measurements again. Thanks again, I will give you update in a lil bit
petehall347
the brandy coffee man
does your meter read zero ohms with probes together ?
lopezluna
Active Member
Ok pin 2 and pin 4 wires removed from awr-104 pcb. Red from transformer to red from transformer = OL
Both red wires from pin 2 and pin 4 remain disconnected from pcb board for all the readings taken.
Pin 2 red wire to chassis ground = OL
Pin 4 red wire to chassis ground = OL
Ok now red wires still disconnect from pcb board I took some readings of pins 2 and 4 again. Pin 2 to chassis ground = 1.345m ohm Pin 4 to chassis ground = 1.425m ohm
lopezluna
Active Member
Both probes together my meter reads 0.1 ohm