After having fun/frustration getting an SX-650 up and running, decided I needed another project. Found an SX-880 on ebay for cheap that 'used to run' but had the power cable cut off. Seemed like it could become a fun project. I'm sure I'll need some help with troubleshooting and diagnosis.
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Here's night 1:
Soldered the power cable back together, pulled the fuses. All ohmed out good, replaced the 5A main fuse and plugged it in. Solid readings on the 1A and 2A fuses. Replaced the burned out dial lamps, and inserted the 2A fuse. Flip power again and lamps come on! yay!
Insert 1A fuses, turn on, no function indicators. No tuning meter movement. No relay clicks. Tap gnd to the relay coil briefly and it clicks on.
So poked around for a while and did some AK searching. Seems the power transistors are finicky on the SX-880s. So at suggestion here: http://www.audiokarma.org/forums/index.php?threads/silent-pioneer-sx-880.316145/, I pulled the solder off the power transistors and resoldered.
Q26 has 63V on the collector, 14.5V on the base, and .... -0.2V on the emitter. Should be 13.5V, which supplies power to the PA3004 protection IC (explains no relay), to the tuner board (no meter movement), and to the led function indicators (no leds).
Pulled Q26 for some diode checks. Good collector-base tests at around 0.56V, but base-emitter junction is no-go.
Path forward:
Looks like I need to put together a parts order. Perusing around AK shows this to be an equivalent: http://www.mouser.com/ProductDetail/ON-Semiconductor/MJE15032G/?qs=HVbQlW5zcXUS0E66TrcxZw==
I'd like to get the receiver powered up and responsive before I go spend $60 on recap supplies... anything else I should buy in the first parts order? I'm thinking probably a larger heatsink for Q26, suggestions?
View media item 10704
Here's night 1:
Soldered the power cable back together, pulled the fuses. All ohmed out good, replaced the 5A main fuse and plugged it in. Solid readings on the 1A and 2A fuses. Replaced the burned out dial lamps, and inserted the 2A fuse. Flip power again and lamps come on! yay!
Insert 1A fuses, turn on, no function indicators. No tuning meter movement. No relay clicks. Tap gnd to the relay coil briefly and it clicks on.
So poked around for a while and did some AK searching. Seems the power transistors are finicky on the SX-880s. So at suggestion here: http://www.audiokarma.org/forums/index.php?threads/silent-pioneer-sx-880.316145/, I pulled the solder off the power transistors and resoldered.
Q26 has 63V on the collector, 14.5V on the base, and .... -0.2V on the emitter. Should be 13.5V, which supplies power to the PA3004 protection IC (explains no relay), to the tuner board (no meter movement), and to the led function indicators (no leds).
Pulled Q26 for some diode checks. Good collector-base tests at around 0.56V, but base-emitter junction is no-go.
Path forward:
Looks like I need to put together a parts order. Perusing around AK shows this to be an equivalent: http://www.mouser.com/ProductDetail/ON-Semiconductor/MJE15032G/?qs=HVbQlW5zcXUS0E66TrcxZw==
I'd like to get the receiver powered up and responsive before I go spend $60 on recap supplies... anything else I should buy in the first parts order? I'm thinking probably a larger heatsink for Q26, suggestions?
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