• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Pioneer SX-1250

xXColdShotXx said:
I may just forget this old piece of crap and throw it in the garbage, can't get a local tech to work on it, he say's "they aren't worth fooling with, parts are too hard to get anymore, and if he did fix it it'd tear up in a week and need something else" and i seem to get attitude from the good techs on these forums. lose/lose situation for me. how do people learn? trial and error. you expected me to take a perfect reading the first time i tried, but i had to figure out how to read the plugs on my own. the sm helped a lil. i had to learn how to read it too for the direction of how to test correctly and board #'s.

Thanks for what help you have given though
Click to expand...

ColdShot , just hang in there . You will be glad you did .
Im not much more experienced than you are at this point , MTF and EW have both helped me through a couple repairs here and im greatful for that.
I have got frustrated and wanted to give up to. But i didnt , just take a day or two off and come back with a fresh head and be patient as MTF said.
I have a 1250 that i want to do in the near future , so ill be watching to see how you do and also learn from what is being posted here . As most of us its all about learning and its not going to happen over night . I still have a very long way to go . Well good luck and just try to stay cool and you will be so happy when this is done . :yes:
 
thanks, harley. i notice you have the spec's 1 & 2 and the sg9800eq, my uncle bought his spec system new back in the 70's around same time as my grandpa bought this receiver i have now, but my uncle gave $5,000 for his back then, but he got all kinds of stuff, both spec peices, the eq, tape, tuner, record player, reel to reel and 1 set of hpm-100's, and he has the set of hpm-100's that came with this receiver i beleive. he now has the spec 1 & 2(not is use anymore) and 4 hpm-100's and 4 yamaha ns-500m's
 
Last edited:
Throwing away a 1250 will earn you a lot of enemies 'round these parts. For one thing, even if the absolute worst happened (burnt transformer), there's a ton of usable parts (cosmetic and otherwise) that could be used to revive other ailing 1250's.
 
If you don't mind, mark, i am just gonna order enough caps, transistors and w/e else i need to fix awr-106(stabilizer board) for now? then i may do the rest some other time if i still feel like it, could you get me a list of other components i need besides the caps, done have those except the 1's on back order/not available. thanks in advance.
i took the board out earlier and looked at it. it had a burnt looking spot top left corner near the resistors with the insulators and tape wrapped around them, and there's some orangish looking components that look old as **** and dried up.
 
Last edited:
Another vote to hang in there coldshot. Threads like this end up being immensely helpful for guys like me because knowledge that is often taken for granted in other threads is truly broken down to basics here.

Plus, once you get that 1250 going, it'll will have been well worth it. I'm definitely envious - even in it's current non-working state.
 
xXColdShotXx said:
If you don't mind, mark, i am just gonna order enough caps, transistors and w/e else i need to fix awr-106(stabilizer board) for now? then i may do the rest some other time if i still feel like it, could you get me a list of other components i need besides the caps, done have those except the 1's on back order/not available. thanks in advance.
i took the board out earlier and looked at it. it had a burnt looking spot top left corner near the resistors with the insulators and tape wrapped around them, and there's some orangish looking components that look old as **** and dried up.
Click to expand...

ok, I'm on it after I get back from the Doctor's office tonight. That other area is the rectifiers and bleeders for the main (big caps) power and that is both typical and expected, and not a problem. I'll double check the component colors on one of my spare boards tonight to be sure...
 
when/if i re-build the AWR-106(stabilizer board) will i have to use dbt on it? and could someone tell me exactly what wires to hook it too, or do i use it like testing dc-offset through the speaker terminal, remember i am still learning as i go. if i can actually figure out how to test and repair electronics i may go to school for it, but we'll have to see how this project pans out. thanks in advance to whoever can offer me the info i seek.
 
I'll keep that in mind. The DBT is needed, and it is a really fancy name for a very simple concept.

You know how a fuse is inserted in one line of the power cord, to burn out if the amperage is exceeded? Instead of a fuse we use a light bulb. It has some interesting quirks that work to our advantage.

The advantage - we (me too) make mistakes, and it saves our <ahem>, preventing smoke and flames....
 
awr-106 awr106 board parts by mtf

awr-106 awr106 board parts mtf

markthefixer said:
Here's the latest complete sx-1250 power supply rebuild parts list, updated to reflect unavailable transistors AND new voltage adjust trimpots - at under 2 bucks each, they're cheap insurance.

Further posts will document the parts for the protection and amplifier board rebuilds. All 4 of these boards are removable easily because they are connectorized, and all the advice above is excellent.


--- --- --- +13v regulator --- --- ---

Q9: 2SD325R-E to-220 bce 35v 3a 10w 40-320hfe 8mhz Q9 pwr +13v pass
512-KSC2073TU to-220 bce 150v 1.5a 25w 4mhz 40-140hfe $0.53

Q10: 2SC945A-R to-92 ecb 50v .1a .25w 50-600hfe 250mhz Q10 darlington dvr
512-KSC2310YBU to-92 ecb 150v .05a .8w 100mhz 40-240hfe $0.11 ea

Q11: 2SC945A-R to-92 ecb 50v .1a .25w 50-600hfe 250mhz q11 feedback
512-KSC1845UBU (ln)to-92 ecb 120v .05a .5w 100mhz 150-800hfe $0.05 ea

D5: WZ-061 6.1v 0.5w zener diode
512-1N5234B Fairchild 6.2V, 0.5W Zener

D6: 1s2473
512-1N4148 Diodes - Small Signal 100V Io/200mA BULK

C15: 47 10V 647-UPW1A470MDD6 47 10V

C16: 22 10V 647-UPW1A220MDD 22 10V

C17: 220 16V 647-UPW1C221MPD 220 16v



Re: beefing things up, Q4 and Q8 come to mind... going from an itty bitty case to a larger case that can dissipate more heat.

*************
--- --- --- +25v regulator --- --- ---
Q4: 2SC1384-R to-92 ecb 50v 1a 1w 50-340hfe 200mhz Q4 +25v pos pass
512-KSC2690AYS to-126 ecb 120/a160 1.2a 20w 155mhz 35-320hfe $0.40


C9: 100 35V 647-UPW1J101MPD 100 63V

--- --- --- -25v regulator --- --- ---
Q8: 2SA684A-R to-92 ecb 50v 1a 1w 50-340hfe 200mhz Q8 -25v neg pass
512-KSA1220YSTU to-126 ecb 120/a160 1.2a 20w 155mhz 35-320hfe $0.39


C10: 100 35V 647-UPW1J101MPD 100 63V

***********

--- --- --- +65v regulator --- --- ---

Q1: 2SD313P-E to-220 bce 60v 3a 30w 40-320hfe 5mhz Q1 pwr +65v pass
512-KSC2073TU to-220 bce 150v 1.5a 25w 4mhz 40-140hfe $0.53

Q2: 2SC869-D to-92 bce 160v 30ma .2w 90hfe ?mhz Q2 darlington dvr
512-KSC2310YBU to-92 ecb 150v .05a .8w 100mhz 40-240hfe $0.11 ea

Q3: 2SC1318-R to-92 ecb 50v .5a .625w 85-340hfe 200mhz q3 feedback
512-KSC1845UBU (ln)to-92 ecb 120v .05a .5w 100mhz 150-800hfe $0.05 ea

D1: WZ-240 24v 0.5w zener diode
512-1N5252B Fairchild 24 V, 0.5W Zener

D2: 1s2473
512-1N4148 Diodes - Small Signal 100V Io/200mA BULK

C1: 220 80V 647-UHE2A221MHD 220 100V 12mm x 31mm

C5: 47 35V 647-UPW1V470MED 47 35V

C7: 22 50V 647-UPW1H220MDD 22 50V

C11: 47 80V 647-UPW2A470MPD 47 100V

VR1: 5k ohm 1 turn potentiometer
652-3386H-1-502LF bourns 1250 1 TURN p.s. Voltage adjust POT 3/8" 500ohms 10%



--- --- --- -65v regulator --- --- ---

Q5: 2SB507P-E to-220 bce 60v 3a 30w 40-320hfe 5mhz Q5 pwr -65v pass
512-KSA940TU_Q to-220 bce 150v 1.5a 25w 4mhz 40-140hfe $0.54

Q6: 2SA628A-D to-92 ecb 25v .1a .15w 55-800hfe 100mhz q6 darlington dvr
512-KSA1013YBU to-92 ecb 160v 1a .9w 50mhz 160-320hfe $0.17

Q7: 2SA720-R to-92 ecb 50v .5a .625w 85-340hfe 200mhz q7 feedback
512-KSA992FBU (ln)to-92 ecb 120v .05a .5w 100mhz 150-800hfe $0.05 ea

D3: WZ-240 24v 0.5w zener diode
512-1N5252B Fairchild 24 V, 0.5W Zener

D4: 1s2473
512-1N4148 Diodes - Small Signal 100V Io/200mA BULK

C2: 220 80V 647-UHE2A221MHD 220 100V 12mm x 31mm

C6: 47 35V 647-UPW1V470MED 47 35V

C8: 22 50V 647-UPW1H220MDD 22 50V

C12: 47 80V 647-UPW2A470MPD 47 100V

VR2: 5k ohm 1 turn potentiometer
652-3386H-1-502LF bourns 1250 1 TURN p.s. Voltage adjust POT 3/8" 500ohms 10%



--- --- --- 5.5v regulator --- --- ---

Q12: 2SD325R-E to-220 bce 35v 3a 10w 40-320hfe 8mhz Q12 pwr +5.5v pass
512-KSC2073TU to-220 bce 150v 1.5a 25w 4mhz 40-140hfe $0.53

Q13: 2SC945A-R to-92 ecb 50v .1a .25w 50-600hfe 250mhz Q13 darlington dvr
512-KSC2310YBU to-92 ecb 150v .05a .8w 100mhz 40-240hfe $0.11 ea



C13: 1000 25V 647-TVX1H102MCD Note: axial capacitor 1000 50V
C18: 47 10V 647-UPW1A470MDD6 47 10V
C19: 47 10V 647-UPW1A470MDD6 47 10V

***************************

and to save a LOT of typing:
mouser.com 's
bom import:
512-KSC2073TU|1
512-KSC2310YBU|1
512-KSC1845UBU|1
512-1N5234B|1
512-1N4148|1
647-UPW1A470MDD6|1
647-UPW1A220MDD|1
647-UPW1C221MPD|1
512-KSC2690AYS|1
647-UPW1J101MPD|1
512-KSA1220YSTU|1
647-UPW1J101MPD|1
512-KSC2073TU|1
512-KSC2310YBU|1
512-KSC1845UBU|1
512-1N5252B|1
512-1N4148|1
647-UHE2A221MHD|1
647-UPW1V470MED|1
647-UPW1H220MDD|1
647-UPW2A470MPD|1
652-3386H-1-502LF|1
512-KSA940TU_Q|1
512-KSA1013YBU|1
512-KSA992FBU|1
512-1N5252B|1
512-1N4148|1
647-UHE2A221MHD|1
647-UPW1V470MED|1
647-UPW1H220MDD|1
647-UPW2A470MPD|1
652-3386H-1-502LF|1
512-KSC2073TU|1
512-KSC2310YBU|1
647-TVX1H102MCD|1
647-UPW1A470MDD6|1
647-UPW1A470MDD6|1
534-4672
534-4672
532-249

on aug 9, 2009 this BOM import works correctly, and has all parts, current price 12.67
Click to expand...

on nov 3, 2010 this bom import works correctly, has all the parts, current price $19.44
and is higher because of the thermal compound
I have to investigate the 220uf 80v original / replacements as to the fit on the board.
results will be added here.
they are size critical. diameter , perhaps height too.
edit - caps changed to ones that will fit.


hmmm, to-220 micas just to be safe and thermal grease too.
534-4672 to-220 mica insulators $0.12 each...........
532-249 1 oz thermal compound $4.71
 
Last edited:
awr107 awr-107 board parts

just the 106 so far,

it (the 106) is now DONE.

I have a 106 here and I am measuring the cap spacings and height limitations.
16mm wide x ~ 30mm tall

647-UHE2A221MHD 220uf 100v 12mm x 31mm - it is now on the post and the BOM list


4 caps needed for the 107 ( awr-107 awr107 )
2x 470 uf 100v ceb (axial) 647-TVX2A471MCD $3.18 ea
2x 470uf 25v cea (radial) 647-UPW1E471MPD $0.47 ea

just an FYI, for more general reference, you can get 8 diodes too:
8x 512-1n4004 for a complete electrical power supply rebuild.

this is complete.
 
Last edited:
I was looking at some pics i took yesterday and found a burnt resistor, here's a pic of it. this is of AWR-106(stabilizer board)
DSCF0916.jpg
 
R6, 8.2k ohms 1/4 watt... did you place the order yet?

part number: 660-MF1/4LCT52R822J

It is part of that -65v regulator circuit that is shorted out. It is probably a casualty rather than a cause.

You will need to check R2, R4, R8, R10, R12 and R14 with an ohmmeter for damage. It may be necessary to unsolder one lead of each to isolate them from the circuit to get an accurate reading.

It will be good practice for you to be able to locate the components on the board, using the service manual as a guide.

also this site: http://www.dannyg.com/examples/res2/resistor.htm
will be a VERY valuable resource deciphering the color codes used on the resistors to identify their resistance values.
 
Last edited:
haven't placed order yet, gotta wait a few days. i hope these are the right readings.

R2 - 2.67 @20K setting
R4 - 2.71 @20K setting
R8 - 1.0 @20K setting
R10 - 22.1 @200k setting
R12 - 16.01 @20k setting
R14 - 1.58 @20k setting
 
Last edited:
xXColdShotXx said:
haven't placed order yet, gotta wait a few days. i hope these are the right readings.

R2 - 2.67 @20K setting
R4 - 2.71 @20K setting
R8 - 1.0 @20K setting
R10 - 22.1 @200k setting
R12 - 16.01 @20k setting
R14 - 1.58 @20k setting
Click to expand...

spot on, A+ 100 % :D

good readings, good resistors
 
do you think that resistor is causing my popping and cracking on left side and right side to barely play through it's own pre-amp, or is there more problems?
 
There may be more damage. get the power supply voltage fixed and maybe that part of the problem goes away. if not, more to do...

The resistor is in the power supply, which provides electricity of the correct voltages to run the different audio circuits, which are completely separate .

The resistor was collateral damage, not the culprit. 91v across that resistance is about 1 watt, and it's a 1/4 watt part. normally it's 65 volts - 24v of the zener diode for 41 volts for 0.20 watts.

The increased voltage could be hurting things that can't tolerate the increased voltage, or things were already hurt (or died), which pulled too much current from the -65v regulator, causing it to short out. It would have been better if it had "opened up", but we weren't that lucky.

Troubleshooting is a process, where things get corrected one at a time, and the changes in symptoms reevaluated.

Maybe the audio circuits will settle down when the voltage is correct
maybe the audio circuit have been damaged by the excess voltage
maybe the audio circuit transistors died first, shorting out the power supply

failed transistors can short out, they can pop open, or they can sit there and crackle, shorting out and then behaving in bursts, or be damaged enough to work somewhat - passing through the wreckage drastically reduced signals.

Maybe if the transistors were transparent, the pops and crackles would translate into microscopic bursts of light, from burning junction material.
 
You must log in or register to reply here.
Back
Top Bottom