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Another inop SX-1250 (Sorry)

This is the list I spoke of earlier. It includes the entire resistor list for the AWH-048 Amplifier board and the proper types of resistors carbon/metal/film/oxide flameproof, wire wound etc.

All of the carbon and metal film resistors I selected are KOA Speer, flame resistant.

I also selected the close tolerance unless Mouser did not have them, in which I went to the 5% value.

Pioneer SX-1250
Power Amplifier Assembly (AWH-048) Resistor List:

R1: 3.3K Carbon Film: 660-CFS1/4CT52R332G
R2: 220K Carbon Film: 660-CFS1/4CT52R224J
R3: 82 Carbon Film: 660-CFS1/4CT26A820G
R4: 47K Carbon Film: 660-CFS1/4CT52R473G
R5: 47K Carbon Film: 660-CFS1/4CT52R473G
R6: 82 Carbon Film: 660-CFS1/4CT26A820G
R7: 62K Carbon Film: 660-CFS1/4CT52R623G
R8: 200K Carbon Film: 660-CFS1/4CT52R204J
R9: 100 Carbon Film: 660-CFS1/4CT52R101G
R10: 100 Carbon Film: 660-CFS1/4CT52R101G
R11: 16K Carbon Film: 660-CFS1/4CT52R163G
R12: 16K Carbon Film: 660-CFS1/4CT52R163G
R13: 1.5K Carbon Film: 660-CFS1/4CT52R152G
R14: 62K Carbon Film: 660-CFS1/4CT52R623G
R15: 220 Carbon Film: 660-CF1/4CT52R221G
R16: 220 Carbon Film: 660-CF1/4CT52R221G
R17: 1K Carbon Film: 660-CFS1/4CT52R102G
R18: 47 Carbon Film: 660-CFS1/4CT52R470G
R19: 47 Carbon Film: 660-CFS1/4CT52R470G
R20: 620 Carbon Film: 660-CFS1/4CT52R621J
R21: 100 Carbon Film: 660-CFS1/4CT52R101G
R22: 100 Carbon Film: 660-CFS1/4CT52R101G
R23: 10K Carbon Film: 660-CFS1/4LT52R103G
R24: 100 Metal Oxide: 1W 279-ROX1G100R
R25: 100 Metal Oxide: 1W 279-ROX1G100R
R26: 1K Metal Oxide: 1W 660-MOS1CT52R102J
R27: 1K Metal Oxide: 1W 660-MOS1CT52R102J
R28: 0.5 Wire wound: 5W 71-CP5-J-0.5
R29: 0.5 Wire wound: 5W 71-CP5-J-0.5
R30: 22 Carbon Film: 660-CFPS1/4CT52R220G
R31: 22 Carbon Film: 660-CFPS1/4CT52R220G
R32: 0.5 Wire wound: 5W 71-CP5-J-0.5
R33: 0.5 Wire wound: 5W 71-CP5-J-0.5
R34: 22 Carbon Film: 660-CFPS1/4CT52R220G
R35: 22 Carbon Film: 660-CFPS1/4CT52R220G
R36: 4.7 Metal Film: 1W 594-5073NW4R700J
R37: 4.7 Metal Film: 1W 594-5073NW4R700J
R38: 10 Metal Oxide: 2W 660-MOS2CT52R100J
R39: 10 Metal Oxide: 2W 660-MOS2CT52R100J
R40: 1.2K Carbon Film: 660-CFS1/4CT52R122G
R41: 1.2K Carbon Film: 660-CFS1/4CT52R122G
R42: 13K Carbon Film: 660-CFS1/4CT52R133G
R43: 13K Carbon Film: 660-CFS1/4CT52R133G
 
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I found a Mouser part number for the uncoated fiberglass sleeving for the extremely Kooky. :D The bad part is it comes in 100 foot rolls (A life time supply) :yes: . Use this number “PIF-240” and look at the Data sheet for the correct size and price. The 18AWG is the smallest size and could be used for the resistor leads. For the 1W resistors, you would use the 9AWG size (.114) (It maybe a tight fit) to cover the resistor itself and for the 2W resistors, you would use the 6AWG size (.162)(enough room) to cover the resistor itself. I have not tried this product or ordered these sizes to know for sure they work. This is only a tip! If you buy some you will have a sale from me.
 
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I do not mean to throw you off your quest but I thought that I'd explain a few things about R's and the reason why things are done the way they are or were.
I do not think I would spec a carbon film resistor for any new design, these days.
I guess you are using them because that is what was as used originally. The reason Pioneer used them at that time is because that is what was commonly available and cheaper. Pioneer also used mostly 5% tolerance R's too, because that is what was readily available, suitable for the application and 1% R's were a premium at that time. These days, 1% are not much of a premium. The only place Pioneer used 1% R's was in the FB ckt for the phono stage to get a more accurate RIAA response.
My choice these days for 1/4W TH R's would be metal film, such as the following for a 3.3Kohm value.
603-MFR-25FBF52-3K3
71-RN60D3301F
660-MF1/4DC3301F

As far as fibreglass sleeving goes, you have to ask why did they use it in the first place?
1) Used it to stand off the R from the pcb, so that the R has more air flow around it and if it gets too hot, not to burn the pcb which were low temp materials at that time(Not FR4 rated). For this, you can also use teflon tubing or ceramic spacers.
2) To contain a R burn out (flames), used for those flame-proof R's.
3) To trap the heat, so that it does not over-heat adjacent comps, such as ecaps. I do have my reservations about trapping heat for a R, this is not such a good idea, as it just makes the R get hotter (limits convection and radiated emission of the heat) and can result in reduced reliability.

All of the carbon and metal film resistors I selected are KOA Speer, flame resistant.
Click to expand...
?
 
discussing after buying implies criticism, while listing before buying promotes discussion.

660-xxxxx............
CF = carbon film
CFS = carbon film reduced Size = 1/8 watt size, 1/4 watt dissipation
CFP = FLAMEPROOF carbon film
CFPS = FLAMEPROOF carbon film reduced size

660-..............G 2%
660-..............J 5%

And because they were not posted, I will have to look up all the original BOM numbers that carry the specifications and add them to the spreadsheet I did to sort this all out. This stuff is not that simple, as evidenced by the fact that omri617 is still waiting on (and I am working on) HIS resistor list for the D7000 amplifier card. Adding them won't help, because I am doing them now, even though real life distractions and obligations are increasing and will peak at the start of March.

edit after a quick look:
these resistors:
R15
R16
R17
R20
R21
R22
R40
R41
BOM calls for flameproof, they aren't,
in fact only:
R30
R31
R34
R35
of the 1/4 watter's are flameproof in the list. I haven't checked the 1 watt and above resistors yet, sorry....
------------
R2
R4
R5
R7
R8
R14
have to look up what the BOM suffux NL denotes in the tuning fork publications making them special.

note: I started this before rcs16 posted and it's past 11 am making it over an hour on this one alone. just so there's a recognition of the time, research etc involved...
 
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What can I do tomorrow? I will have some free time in the afternoon. I would like to go through this process to get a better understanding.
 
zebulon1 said:
What can I do tomorrow? I will have some free time in the afternoon. I would like to go through this process to get a better understanding.
Click to expand...

read the tuning fork publication on resistors, coincidentally it is the exact first post in the STICKIED ^^^^ thread. :D

Then read the 660 resistor series data sheet.

I still haven't "cracked" the NL suffix to find "low noise" resistors, haven't looked at the awh-048 schematic yet either to see where they are, nor dug out a board to eyeball them...


did it: blue band, found all six of them. offset, feedback and input diff

r2 220k input resistance to ground
r4 47k offset voltage generator divider
r5 47k offset voltage generator divider
r7 62k offset injection
r8 220k emitter resistor on input differential pair
r14 62k feedback resistor.

believe it or not:
carbon film small size 5% 1000ppm/deg c
660-CFS1/4CT52R224J $0.15 ea price break at 5000

carbon film normal size 5% 700ppm/deg c
660-CF1/4CT52R224J $0.15 ea price break at 5000


But a far superior choice is less expensive!!
metal film, 1% 100ppm/deg c
660-MF1/4DCT52R2203F $0.06 ea price break at 5000
 
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I read that Tuning fork last night. Nice it was on top of the "Q". I will read it again but I didn't think it held any special or particular “Pioneer” advice on resistor selection. I did learn about the differences in choosing the correct types for an application. I guess I saying it was general in nature.
 
Look back at my post, although I can't prove it yet with the data sheets, metal film resistors will have lower noise than the carbon film as well as being half the price and 1% tolerance to boot.
 
Great! Thanks for your time spent.
I messed up on the emitter resistors. I had .47 ohm listed. They should be the ones you advised; 71-CP5-J-0.5
I made the change (edit) on the original post.
 
I am over my head! Frustrated: can you tell! I have completed the fix and recap up to the last board (EQ). After the replacement of the caps and transistors on the EQ board I powered up and lost the function lights. After checking voltages on the Stabilizer board I found I had lost the +65 regulated supply and hence the 65 volt supply to the EQ board and Amp boards (048) and lights. Checking and looking for a short in the EQ board was difficult because nothing I checked took any obvious path to ground. No visual clues either. I removed Q11 and Q12 to isolate the +65 supply input to the board, repaired the Stabilizer board and got the 65 volts back. Along with the lights and protection.

I then replaced all the components on the EQ board. As I was removing them I was bench checking each one. All tested good. I powered up the set and got lights and thought all was well. NOT! Now I had 31 volts regulated and no protection. Repaired the Stabilizer once again and after powering up I lost all the +65 volt supply.

How can I trouble shoot this with out loosing my power supply voltage? The EQ Board seems to run on 31 volts but not 65.
 
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You might want to double check the pin layout here.
Q11: 2SC1735: 512-KSC2383YTA
2sc1735 is a BEC Layout..
512-KSC2383YTA is a ECB Layout.
you might want to double check the pin layouts in the other subs, to be sure.
 
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I used MTF’s list posted 08-20-13:

http://www.audiokarma.org/forums/showthread.php?t=420950&page=7

EQ board (AWF-021-A)

sx-1250,awf-021,q1,2sa726,ltp-L,,,,,512-KSA992FBU
sx-1250,awf-021,q2,2sa726,ltp-R,,,,,512-KSA992FBU
sx-1250,awf-021,q3,2sa726,ltp-L,,,,,512-KSA992FBU
sx-1250,awf-021,q4,2sa726,ltp-R,,,,,512-KSA992FBU
sx-1250,awf-021,q5,2sc1775,vas-L,,,,,512-KSC1845FTA
sx-1250,awf-021,q6,2sc1775,vas-R,,,,,512-KSC1845FTA
sx-1250,awf-021,q7,2sc1775,out dvr-L,,,,,512-KSC1845FTA
sx-1250,awf-021,q8,2sc1775,out dvr-R,,,,,512-KSC1845FTA
sx-1250,awf-021,q9,2sa872,out dvr-L,,,,,512-KSA992FBU
sx-1250,awf-021,q10,2sa872,out dvr-R,,,,,512-KSA992FBU
sx-1250,awf-021,q11,2sc1735,pass +49,,,,,512-KSC2690AYS
sx-1250,awf-021,q12,2sc869,err amp +,,,,,512-KSC1845FTA
sx-1250,awf-021,q13,2sa850,pass -49,,,,,512-KSA1220AYS
sx-1250,awf-021,q14,2sa628,err amp -,,,,,512-KSA992FBU

Thanks KutzerTrans anyway. I have a Peak DCA55. It spells out the pin configurations and types of Transistors. What’s really nice is it gives the transistor gain. Very handy!
 
The datasheet on the 1735 is converting to a 1730 showing it as a bec. I'm not sure about this one. Do you have another 2sc1735 handy that you could check outside the circuit??
i know you said you checked it. it wouldn't hurt to do it again. Better to know now that chase your tail for a week.
You Wrote on post # 54-----Q11: 2SC1735: 512-KSC2383YTA
Above you have q11,2sc1735,,,,512-KSC2690AYS
Did you mean KSC2690ays?? its a to-126
 
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Pin 9 takes the output of the q11 q12 circuit OFF BOARD.

So the problem could lie elsewhere. Like the flat amp assembly. Pin 11 to C7. Backwards c7?

Nothing easy to disconnect on the eq board to isolate pin 9.

Think about when the +65 last worked and EVERYTHING you did since then to when it blew the +65.

Should the problem be a short somewhere off the eq board I'm surprised Q11 survived and R44 (150 ohms 1/4 watt) or D5 hasn't been smoked. To that end, check the WIRES carefully!!
(also check D5 and the pin 9 voltage of +49v when you think you have it working)
 
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just in case you missed this i will repeat it..
On Post 54 you wrote:Q11: 2SC1735: 512-KSC2383YTA
Above you have:2sc1735,pass +49,,,,,512-KSC2690AYS
Did you mean to write 512-KSC2690AYS ??
 
I originally used Matts list and after having trouble I replaced the EQ board components with MTF’s list which I posted above.

I will check for mis-installed transistors and orientation. Check MTFs suggestions and retrace my steps carefully.
 
512-KSC2383YTA to-92L ecb 160v 1a .9w 50mhz 160-320hfe $0.17
512-KSC2690AYS to-126 ecb 120/a160 1.2a 1.2w/20w 175mhz 35-320hfe $0.40


OLD and NEWER lists, work done (and "lost") and repeated years apart.

YES it's a TO-126, which can have a heat sink stuck on it easily if it's getting warm, and it might survive faults that would fry the other which is a TO-92L.

And we don't realy bother with the old pinouts, as we start fresh with a new transistor,, matching the symbol on the board with the layout specified in the data sheet - the Pioneer manuals have been shown to have wriong pinouts, so they are a GUIDE until proven correct by examining the reality of a working unit and that transistor's relation to the symbol on the board, they usually seemed to get THAT part of it correct.
 
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