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No voltage on pins 8-19 on SX-1050 awr 103 board????!!!!

Good catch, sometimes you can look right at something and not see it. At times you would not believe the checking I do before I solder in the transistor. I'd rather sweat getting it in right, rather than figure out what the $#@# went wrong...

I'm blind to my own spelling errors....

And as you have seen, I occasionally reverse number pairs.

My "trick" for a triangular lead arrangement is to align the two end wires with their respective contacts, then bend the center either right or left to it's hole....
for neatness sometimes I scootch the whole shebang over to center it a little more attractively on the triangle.

I would still check the diodes, just in case, because the (raw dc = +78.8) +60 was also running on just one (FU2) fuse, and IT'S voltage was LOTS better.

Once you have it running again, please measure the voltage ACROSS R1 and R19 those 10 ohm multi-watt resistors, knowing the resistance we can calculate the current being drawn on both supplies. It could be the - voltages are being loaded down somewhere. This is one of the few instances where ungrounded voltage meaurements are taken.

nite nite, I'm toast... sigh ning off till tomorow.
 
markthefixer said:
There is a science fiction story about a guy who became VERY important, because he could ADD NUMBERS without a machine, on PAPER... Nobody understood the old "legacy" code that did it.
Click to expand...

I liked that story too.

Everyone had used computers for so many thousands of years that no one had ever needed to learn it longhand. Also, computers had got smaller and smaller.
Then it was realised this guy was the ultimate !! He could do maths in his head without a computer at all....... People were amazed at how he'd work things out in his head or with pen and paper. Even the addition of 2+3=5 had them gasping in disbelief.

I think that in the end, the military made him teach others so that they could be put into missiles as human "smart" guidance systems......... something like that...
 
After straigening out Q11 5.4 Voltages dropped to 7.45v Need to replace Q13. will do so tomorrow and see what we have. Asta
 
Steve 1050 said:
Pin Voltages for pins 1-3 (AWR 103) are.23.55 ,78.4 ,56.0? diodes 3&4 (AWR 104) tested good
Click to expand...

1) + 23.55 good
2) + 78.4 good
3) - 56.0 uh-oh....

What are the voltages ACROSS R1 (10 ohms) and R19 (10 ohms). R19 will tell if the the -56.0v instead of -78 is because of a large amount of current being drawn.

What were the pins 18 & 19 (+5.4v) after Q13 was replaced? They DO depend upon the pins 5 & 6 (+13v) .

I took a closer look at the relationship between the voltages on pins 5,6 and 18,19. If you use this calculation, and assume 17.95 volts on 5,6 then

( 17.95 / 13.00 ) x 5.4 = 7.45 volts.... look familiar ????? we NEED to bring the pins 5&6 voltages down to 13, because Q12 and Q13 are operating correctly (sorry! should'a caught that yesterday!!) on the garbage in-garbage out principle. D4 is a 6.1v zener,

which just led me to check my parts list on page 2 of this thread.... and .... I sort of blew it!!! da##it... I say "wz-14" for D3, D4 , but 512-1n5234b is the correct part number for the correct 6.2 volt zeners. If you caught that, ok... otherwise i would check all the zeners (d1, d2, d3, d4) by measuring across them to be sure the right ones are in the right place.
 
Pins 5 & 6 are at 18.6V after replacing Q13. Pins 18,19 are at 8.26V. Dumb question of the night, how do I measure across R1 and R19? I seem to have forgotten. Diodes 1-4 were replaced in their respective spots after double checking part #'s on packaging. all part #'s were triple checked against mouser #'s you provided. I did notice the duplication but sort of chalked it up to your being tired. since the part #'s on the schematics were also different for those diodes.
 
Steve 1050 said:
Pins 5 & 6 are at 18.6V after replacing Q13. Pins 18,19 are at 8.26V. Dumb question of the night, how do I measure across R1 and R19? I seem to have forgotten. Diodes 1-4 were replaced in their respective spots after double checking part #'s on packaging. all part #'s were triple checked against mouser #'s you provided. I did notice the duplication but sort of chalked it up to your being tired. since the part #'s on the schematics were also different for those diodes.
Click to expand...

Not dumb question, the resistors have two leads, and the voltmeter probeS go to one each at the same time, polarity is unimportant for now, just the magnitude of the voltage across the ten ohms will give us a current reading using ohm's law: current = volts divided by ohms.

regarding the 13v regulator, q10 and q11 went in wrong and were replaced, but Q9 tested good and was left in? Do you have another Q9? Or Q1, I specified the same one (KSC2073:150v,1.5a,25w... hard to blow up unless the base to emitter voltage gets over 5 volts or so... )
Now we troubleshoot the +13v regulator too:
Please take ground referenced voltage readings at the emitters, bases and collectors of Q9, Q10 and Q11 (9 readings in total, don't cheat, if they SAY they're connected on the schematic, don't write the same number down twice, READ it at the component lead. This can spot strange solder joints OR bad traces on the board, cracks can be VERY tiny).

Thus to summarize:
2 voltages, read across r1 and R19
9 voltages, 3 each for 3 transistors, Q9, Q10, Q11. unless q9 is replaced and 13v is obtained at pins 5 & 6.
 
since I have to work tomorrow AM, I am going to call it a night. it is now 1:27AM. Will post readings tomorrow. BTW I do have extras for Q1 & Q9. Later!
 
Steve 1050 said:
since I have to work tomorrow AM, I am going to call it a night. it is now 1:27AM. Will post readings tomorrow. BTW I do have extras for Q1 & Q9. Later!
Click to expand...

Sounds good, west coast huh...

Midwest... it's 3:30 here and I'm toast...
 
Voltage readings for R1=.457v, R19=.213V
Q9
E=19.25
B=20.05
C=20.91

Q10
E=19.87
B=19.72
C=20.65

Q11
E=6.94
B=9.58
C=19.96
 
Steve 1050 said:
Great the only transistors I forgot to order duplicates of!
Click to expand...

If you are going to order some, wait, and I will come up with something with the SAME pinout. I should have done that originally. That is what I am doing RIGHT now...

Are you sure that they are in right, I was just examining the board layout etc...

You know that :
1) the manual shows the foil side of the board
2) the component side should have a symbol silkscreened on the board showing the leads...

Do you feel like taking them back out and testing them?

edit:
2sc945..... to-92 .. .. ecb 50v 0.1a 0.25w 150mhz 50-600hfe
512-KSC945CLTA to-92 ebc 50v .15a .25w 180mhz 40-700hfe $0.05 ea <<<< was
512-KSC1845UBU to-92 ecb 120v .05a .5w 100mhz 150-800hfe $0.05 ea <<< new try<<< less current but that's ok here...
 
Taking them out not a problem , I double checked the pinout befor I inserted them,and again before I applied solder, but that being said, mistakes can be made. will pull and check.
 
Whenever a transistor is biased on, there is about a 0.6v difference between the emitter and the base. polarity of that 0.6v depends upon the polarity of the transistor i.e. pnp/npn.

I'm not sure if i mentioned my method of aligning transistor flats on a triangular lead pattern:
use the ouside leads in the line (not the center one) and match them up on a line with their two pcb holes, then the base will either be 90 degrees to the front or the back of the flat. bend the center lead to it....

When you test transistors, you have done all six permutations of the dmm diode test?

Those q9, q10 and q11 readings weren't very stable huh? The shared q9 & q10 collectors were 0.34 v different, Q10 emitter and q9 base were 0.18v different and Q11 collector and q10 base were 0.24 different.

Were the transistors getting hot?

What I would expect to see is 6.1v on Q11 emitter, 6.7v on Q11 base and some indeterminate value (about 14.4v) on the Q11 collector which results in about 13.2v at the emitter of q9 which goes through the r25, r26, r27 & r28 voltage divider and ends up with the 6.7v on the base of Q11. Q11 is the error amp and wants to keep about a 0.6v positive difference between it's emitter and base and will vary it's collector current to get that base - emitter bias. It's the engineers job to get the right resistor values around it to take advantage of that fact. The same holds true for Q10 and Q11, each will vary their collector to emitter current to get 0.6 volts from it's base to emitter.

thus the ideal readings are: q9 emitter 13.2
q9 base, q10 emitter 13.8 (+0.6 for Q9)
q10 base, q11 collector 14.4 (+ 0.6 for Q10)
q11 base (it wants 6.1+0.6 for Q11) and gets 6.7 = (13.2 * (r26||r28/((r26||r28)+(r25||r27))) from the voltage divider fraction of 13.2
q11 emitter 6.1 , the zener diode's voltage.

Thus examing the circuit, using the base emitter voltages, we see that q9 has 0.8v and may be ok (turned on hard), q10 has a -0.15 and is weird (turned off hard) , and q11 has 2.64v which has it turned on hard, trying to bring down it's collector voltage from 19.96 to 14.4v ...... ASSUMING that they are connected correctly and undamaged.
 
I'm on my way to work, but I pulled Q10 and Q11 and diode checked them. have you ever seen a transistor change e.c.b designations? I thought not. upon checking Q10 I realized that the leg arrangement was ECB, same as original, reading were "good" with that lead config. Q11 tested as good in its stated EBC config. Flipping Q10 to account for the leg config I reinstalled and checked pin 5,6and 18,19 voltages . pins 18,19 were back to 5.4Vand pins 5.6 were at 13V. Since I'm not sure I really saw what I thought I saw. I will recheck after work and post results.
 
Wow, GOOD CATCH!! Either it is a mismarked transistor, or one of the originals mixed in that was good. With the to-92 being so small, I will check to see if the replacement ksc945 omits the ks part of the designator on the package. I do know that the original 2sc945 DOES omit the 2s and is marked c945.

The proof is in the pudding so to speak, the correct 5.4 and 13v outputs makes whatever it is now true.

.........

yup the ksc945 is marked c945 and lch12 on the ones I have (obtained at the start of the month). No indication of a "F".

hmmm... that's serious, two transistors with different pinouts and almost identical markings in the same equipment.... I'm going to have to rethink that transistor as a replacement.....


edit: I'm both somewhat paranoid and methodical, I have big squares of the black conductive foam that the removed transistors / IC's go into while the replacements are aligned on another square, and before a transistor goes in I have a polarity and lead-identifying functional transistor tester that I run them through first, as well as the pinouts and specs of the originals and replacements in front of me as I do it. Depending upon circumstances I either photograph the original board before doing anything, or sketch the layouts and orientations. I spend less time doing that then figuring out what went wrong... you saw part of that with the parts list back on page 2 of the thread.
 
More than likly a mismarked trans as all the originals are in a bag set aside,and marked as orig.
so what do we do about the -54.6V on pin3?
 
Steve 1050 said:
More than likly a mismarked trans as all the originals are in a bag set aside,and marked as orig.
so what do we do about the -54.6V on pin3?
Click to expand...

When those transistors came in, were they embedded in a cardboard tape, or were they loose? This is disturbing....

markthefixer said:
1) + 23.55 good
2) + 78.4 good
3) - 56.0 uh-oh....

What are the voltages ACROSS R1 (10 ohms) and R19 (10 ohms). R19 will tell if the the -56.0v instead of -78 is because of a large amount of current being drawn.
Click to expand...

One probe to each lead of the resistor, and I expect to see a lot less than 2 volts across the resistor. The calculation will be volts divided by ohms giving a result in amps. Thus for example 0.2v / 10 ohms = 0.02 amps or 20 milliamps.

Once the voltages ACROSS R1 (10 ohms) and R19 (10 ohms) have been read, you can try opening up either R19 or pin 3, which will interrupt any current flow and then we will see what the unloaded voltage goes to, because there is a 470uF 80v capacitor (C10) on the rectifier/fuse board. Was that capacitor replaced, or is it original? I specified parts for this board and didn't mention the other board, so it wouldn't surprise me... but D2, D3, D4 and D5 are NEW, correct?

Is Q5, Q6, Q7 or Q8 getting hot, or is C10 on the other board getting warm? That would be a clue....
 
No work has been done on 104 board diodes 3&4 were check and tested good. All mentioned transistors are "cool" to the touch. C10 is also "Cool".Voltage on R1=.487V, R19=.213V . I think transistors were packed loose.
 
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