SA-9800 Frys Speakers!
- Thread starter ehc68
- Start date
ehc68 said:
That's a good resistor, plus Radio Shack really doesn't have resistors anymore, just a few caps, diodes and transistors nowadays.
I want to find those zeners and run them through the dmm diode test to see and advise on the readings..... but probably won't find it tonight.
You can try the diode test (not ohmmeter test) on the zener diode CAREFULLY taken out of circuit, and if it's shorted you will know quick enough...
Any questions on the dmm diode test, see EW's sticky about bipolar transistor testing in the vintage solid state forum.
when I find it, that will be my next post....
edit: oh, here's a spot of good news, the Q9 & Q11 circuit is working, once we get 6v on the emitter of Q9, everything will be ok there.
I'm wondering if a fault in the q1,q3,q5,q7 circuit is badly affecting the diode's voltage. but I'm not sure how to isolate it, because once the 77.5v goes away from Q1's emitter, a needed bias for Q9 goes away, depriving the zener diode of current completely as the 12v at Q11's emitter will disappear. I have to think on this... meanwhile a re-check of Q7 would be a good idea, with the results posted.
found them, 1n5233b 6v .5w and 1n4735 6v 1w
in one direction the test reads "OL" as in no conduction
the other direction the test reads about 725 or so on several examples of both types.
ehc68
My SX-1050
Ok...well I tested Q2, Q4, Q8, Q10 and Q12.
Doesn't look good at all. Q2, Q4, Q8 and Q12 all look bad. I'm not sure about Q6 because it's another k34 jfet and I don't know how to check those (I'll look and see if Echowars explains those on that post).
So in other words, other than the unknown Q6, the only GOOD one appears to be Q10.
Here's what I get on Q2, Q4, Q8, Q10 and Q12......
Q2(NPN)
base, emitter - 004mv (continuity)
base, collector - 564mv
base, emitter (-,+) - 004mv (continuity)
base, collector (-,+) - little drop
collector, emitter (+,-) - little drop
Q4(NPN)
base, emitter - nothing
base, collector - nothing
base, emitter (-,+) - 679mv
base, collector (-,+) - 659mv
collector, emitter (+,-) - nothing
Q8(NPN)
base, emitter - nothing
base, collector - nothing
base, emitter (-,+) - 682mv
base, collector (-,+) - 662mv
collector, emitter (+,-) - nothing
Q10(PNP):yes:
base, emitter - 664mv
base, collector - 656mv
base, emitter (+,-) - nothing
base, collector (+,-) - nothing
collector, emitter (-,+) - nothing
Q12(NPN)
base, emitter - nothing
base, collector - nothing
base, emitter (-,+) - 595mv
base, collector (-,+) - 593mv
collector, emitter (+,-) - nothing
Doesn't look good at all. Q2, Q4, Q8 and Q12 all look bad. I'm not sure about Q6 because it's another k34 jfet and I don't know how to check those (I'll look and see if Echowars explains those on that post).
So in other words, other than the unknown Q6, the only GOOD one appears to be Q10.
Here's what I get on Q2, Q4, Q8, Q10 and Q12......
Q2(NPN)
base, emitter - 004mv (continuity)
base, collector - 564mv
base, emitter (-,+) - 004mv (continuity)
base, collector (-,+) - little drop
collector, emitter (+,-) - little drop
Q4(NPN)
base, emitter - nothing
base, collector - nothing
base, emitter (-,+) - 679mv
base, collector (-,+) - 659mv
collector, emitter (+,-) - nothing
Q8(NPN)
base, emitter - nothing
base, collector - nothing
base, emitter (-,+) - 682mv
base, collector (-,+) - 662mv
collector, emitter (+,-) - nothing
Q10(PNP):yes:
base, emitter - 664mv
base, collector - 656mv
base, emitter (+,-) - nothing
base, collector (+,-) - nothing
collector, emitter (-,+) - nothing
Q12(NPN)
base, emitter - nothing
base, collector - nothing
base, emitter (-,+) - 595mv
base, collector (-,+) - 593mv
collector, emitter (+,-) - nothing
Q2 is the only NPN and it is bad.
NPN has the arrow pointing OUT, PNP has the arrow pointing IN, also 2sa and 2sb are PNP's while 2sc and 2sd are NPN's....
Q4, Q8, Q10, Q12 are ALL PNP's and yet Q10 you give results in a form that looks like an NPN, and you think it is good in that form. it's FINE for an NPN, but you call it a PNP.
In summary, while q10 confuses me as to the results order, it looks good, in fact ALL look GOOD EXCEPT Q2, that looks like toast...
to pierce the confusion, (in case the order of the transistors got mixed) list the actual part numbers printed on the transistor with the test results.
Also the 2S is an assumed prefix, so for example 2SC1735 would be marked C1735 .
here is a link to a jfet testing procedure that EchoWars posted, but
The actual document is attached at the bottom of THIS page.......
here is a page of actual transistor test results in a format remarkably similar to what you are using, feel free to copy the text and add YOUR numbers...
first the PNP:
black lead to base, red lead to collector, result = 675
black lead to base, red lead to emitter, result = 688
red lead to base, black lead to collector, result = OL = No conduction
red lead to base, black lead to emitter, result = OL = No conduction
black lead to emitter, red lead to collector, result = OL = No conduction
red lead to emitter, black lead to collector, result = OL = No conduction
next the NPN:
black lead to base, red lead to collector, result = OL = No conduction
black lead to base, red lead to emitter, result = OL = No conduction
red lead to base, black lead to collector, result = 677
red lead to base, black lead to emitter, result = 680
black lead to emitter, red lead to collector, result = OL = No conduction
red lead to emitter, black lead to collector, result = OL = No conduction
here is an old image I modified for bipolar transistors, the jfet image is below it:
Here is the jfet testing image:
NPN has the arrow pointing OUT, PNP has the arrow pointing IN, also 2sa and 2sb are PNP's while 2sc and 2sd are NPN's....
Q4, Q8, Q10, Q12 are ALL PNP's and yet Q10 you give results in a form that looks like an NPN, and you think it is good in that form. it's FINE for an NPN, but you call it a PNP.
In summary, while q10 confuses me as to the results order, it looks good, in fact ALL look GOOD EXCEPT Q2, that looks like toast...
to pierce the confusion, (in case the order of the transistors got mixed) list the actual part numbers printed on the transistor with the test results.
Also the 2S is an assumed prefix, so for example 2SC1735 would be marked C1735 .
here is a link to a jfet testing procedure that EchoWars posted, but
The actual document is attached at the bottom of THIS page.......
here is a page of actual transistor test results in a format remarkably similar to what you are using, feel free to copy the text and add YOUR numbers...
first the PNP:
black lead to base, red lead to collector, result = 675
black lead to base, red lead to emitter, result = 688
red lead to base, black lead to collector, result = OL = No conduction
red lead to base, black lead to emitter, result = OL = No conduction
black lead to emitter, red lead to collector, result = OL = No conduction
red lead to emitter, black lead to collector, result = OL = No conduction
next the NPN:
black lead to base, red lead to collector, result = OL = No conduction
black lead to base, red lead to emitter, result = OL = No conduction
red lead to base, black lead to collector, result = 677
red lead to base, black lead to emitter, result = 680
black lead to emitter, red lead to collector, result = OL = No conduction
red lead to emitter, black lead to collector, result = OL = No conduction
here is an old image I modified for bipolar transistors, the jfet image is below it:
Here is the jfet testing image:
ehc68
My SX-1050
I'm sorry Mark!!!
I THOUGHT I had it figured out.....obviously not.
I thought that transistors with a lead arrangement of BCE were NPN and those with ECB were PNP (reversed leads=reversed polarity when testing PNP)......my bad!!
The format I was going by was from the diode test page of Echowars as far as probe orientation (at least, I'm pretty sure that was the same format he used), I THINK it was the fact that I didn't know the differences between NPN and PNP that confused everything......that and my typo on Q10.
Anyway, I copied your text and added my results. I tested them all again and specified part numbers for each.
Q4 PNP A904:
black lead to base, red lead to collector, result = 657
black lead to base, red lead to emitter, result = 677
red lead to base, black lead to collector, result = nothing
red lead to base, black lead to emitter, result = nothing
black lead to emitter, red lead to collector, result = nothing
red lead to emitter, black lead to collector, result = nothing
Q8 PNP A904
black lead to base, red lead to collector, result = 660
black lead to base, red lead to emitter, result = 679
red lead to base, black lead to collector, result = nothing
red lead to base, black lead to emitter, result = nothing
black lead to emitter, red lead to collector, result = nothing
red lead to emitter, black lead to collector, result = nothing
Q10 PNP A733
black lead to base, red lead to collector, result = 653
black lead to base, red lead to emitter, result = 660
red lead to base, black lead to collector, result = nothing
red lead to base, black lead to emitter, result = nothing
black lead to emitter, red lead to collector, result = nothing
red lead to emitter, black lead to collector, result = nothing
Q12 PNP B682
black lead to base, red lead to collector, result = 590
black lead to base, red lead to emitter, result = 592
red lead to base, black lead to collector, result = nothing
red lead to base, black lead to emitter, result = nothing
black lead to emitter, red lead to collector, result = nothing
red lead to emitter, black lead to collector, result = nothing
This does look much better....I had it ALL screwed up!
Again, my apologies!
OK...now for the jfet, Echowars says to set ohmmeter to R x 100 scale.
The ohmmeter section of my meter is.. 400, 4K, 40K, 400K, 4M, 40M, 400M.
Doesn't look like I have a 100 scale.:scratch2:
I THOUGHT I had it figured out.....obviously not.
I thought that transistors with a lead arrangement of BCE were NPN and those with ECB were PNP (reversed leads=reversed polarity when testing PNP)......my bad!!
The format I was going by was from the diode test page of Echowars as far as probe orientation (at least, I'm pretty sure that was the same format he used), I THINK it was the fact that I didn't know the differences between NPN and PNP that confused everything......that and my typo on Q10.
Anyway, I copied your text and added my results. I tested them all again and specified part numbers for each.
Q4 PNP A904:
black lead to base, red lead to collector, result = 657
black lead to base, red lead to emitter, result = 677
red lead to base, black lead to collector, result = nothing
red lead to base, black lead to emitter, result = nothing
black lead to emitter, red lead to collector, result = nothing
red lead to emitter, black lead to collector, result = nothing
Q8 PNP A904
black lead to base, red lead to collector, result = 660
black lead to base, red lead to emitter, result = 679
red lead to base, black lead to collector, result = nothing
red lead to base, black lead to emitter, result = nothing
black lead to emitter, red lead to collector, result = nothing
red lead to emitter, black lead to collector, result = nothing
Q10 PNP A733
black lead to base, red lead to collector, result = 653
black lead to base, red lead to emitter, result = 660
red lead to base, black lead to collector, result = nothing
red lead to base, black lead to emitter, result = nothing
black lead to emitter, red lead to collector, result = nothing
red lead to emitter, black lead to collector, result = nothing
Q12 PNP B682
black lead to base, red lead to collector, result = 590
black lead to base, red lead to emitter, result = 592
red lead to base, black lead to collector, result = nothing
red lead to base, black lead to emitter, result = nothing
black lead to emitter, red lead to collector, result = nothing
red lead to emitter, black lead to collector, result = nothing
This does look much better....I had it ALL screwed up!
Again, my apologies!
OK...now for the jfet, Echowars says to set ohmmeter to R x 100 scale.
The ohmmeter section of my meter is.. 400, 4K, 40K, 400K, 4M, 40M, 400M.
Doesn't look like I have a 100 scale.:scratch2:
Last things first, with probable multiple edits:
Diode test, done just like 2 leads of a transistor, with the DMM set on diode test.
On that last image I posted, the diode is listed under the transistors.
The OL would read the zener voltage if it was capable...
Q7 test was to be out of circuit... the voltages are way messed up, so with our transistor testing being on the same page, it may prove informative.
Q6 on first glance looks good, BUT I will repeat with a n channel jfet here in a little while because that voltage looks high, AND I'm reserving judgement until I do...
Diode test, done just like 2 leads of a transistor, with the DMM set on diode test.
On that last image I posted, the diode is listed under the transistors.
markthefixer said:
The OL would read the zener voltage if it was capable...
Q7 test was to be out of circuit... the voltages are way messed up, so with our transistor testing being on the same page, it may prove informative.
Q6 on first glance looks good, BUT I will repeat with a n channel jfet here in a little while because that voltage looks high, AND I'm reserving judgement until I do...
ehc68
My SX-1050
Ok, I pulled Q7.....here are the results....
Q7 - C2631 NPN (C1914 replacement) ECB
black lead to base, red lead to collector, result = nothing
black lead to base, red lead to emitter, result = nothing
red lead to base, black lead to collector, result = 640
red lead to base, black lead to emitter, result = 655
black lead to emitter, red lead to collector, result = nothing
red lead to emitter, black lead to collector, result = nothing
:scratch2: :scratch2: :scratch2:.......bad??
Q7 - C2631 NPN (C1914 replacement) ECB
black lead to base, red lead to collector, result = nothing
black lead to base, red lead to emitter, result = nothing
red lead to base, black lead to collector, result = 640
red lead to base, black lead to emitter, result = 655
black lead to emitter, red lead to collector, result = nothing
red lead to emitter, black lead to collector, result = nothing
:scratch2: :scratch2: :scratch2:.......bad??
ehc68 said:
GOOD...
looks good to me... but the in circuit voltage readings puzzle me more now....--- ---- ------ ------- -------- -------- ---------------
ehc68 said:
That was out of circuit, right?? If so:
YECCCHHHH
uke: PM me your mailing address, I have some 0.5 watt 6v zener diodes at my elbow now... (and some 1 watters, which you don't need), I will try to beat the 2:30 pm mail pickup here, if I get the address in time, so you get it before the weekend. Did you get more than one 2sc1735 (for Q2) ?
------- -------- ---------- --------- ---------- ----------
OK, I just tested a bunch of n-channel jfets, according to the previously discussed procedure.
black lead to gate, red lead to drain, diode test result = no conduction = OL
black lead to gate, red lead to source, diode test result = no conduction = OL
red lead to gate, black lead to drain, diode test result = 748 (mV)
red lead to gate, black lead to source, diode test result = 748 (mV)
black lead to source, red lead to drain, TRUE ohms test result is = 200 ohms
red lead to source, black lead to drain, TRUE ohms test result is = 200 ohms
Thus the readings you got in post #66 for Q6 (1959 mV) is a bit suspect, IF this had been measured on a NEW jfet, then it would be less of an issue.
When you got the transistors, how many extras did you get?
PLUS< remember I need your mailing address to send the zener diodes to, ASAP....
ehc68
My SX-1050
The diode check was done out of circuit.
I checked Q6 again, and this is what I got this time
black lead to gate, red lead to drain, diode test result = nothing
black lead to gate, red lead to source, diode test result = nothing
red lead to gate, black lead to drain, diode test result = 1984 (mV)
red lead to gate, black lead to source, diode test result = 1984 (mV)
black lead to source, red lead to drain, TRUE ohms test result is = 385 ohms
red lead to source, black lead to drain, TRUE ohms test result is = 385 ohms
These are all approximate readings. With red lead to gate, black lead to drain,
the meter will jump real quick to the 2000 range them drop between 1974 and
1984,the same thing happens with red lead to gate, black lead to source.
Also, the longer I keep the probes on the leads the more the meter will climb up
real slowly without ever seeming to stop. What's really strange to me is that... let's
say it starts at 1950, and I let it go until 1980...if I take the probes off and then
back on again, rather than starting back at 1950, it will continue from whatever point it
left off at previously.
The ohm reading was taken with my meter set on 400.
I'm sending you a PM with my address, however there really isn't a hurry because unfortunately, I didn't order ANY other transistors so I'll have to order Q2 anyway.
How many of Q2 or any others should I get and should I get another C4 cap or is that not necessary......also could you recommend a vendor for these...I would rather not use CP again. I haven't tried Mouser for these yet....that might be an option.
Mark, seriously....thank you VERY much for sending the diode. Let me know what I owe you!! Also, thank you very much for all your time, effort and patience with helping me out on this amp, I really do appreciate it!!
Anyway...the PM is on it's way......
I checked Q6 again, and this is what I got this time
black lead to gate, red lead to drain, diode test result = nothing
black lead to gate, red lead to source, diode test result = nothing
red lead to gate, black lead to drain, diode test result = 1984 (mV)
red lead to gate, black lead to source, diode test result = 1984 (mV)
black lead to source, red lead to drain, TRUE ohms test result is = 385 ohms
red lead to source, black lead to drain, TRUE ohms test result is = 385 ohms
These are all approximate readings. With red lead to gate, black lead to drain,
the meter will jump real quick to the 2000 range them drop between 1974 and
1984,the same thing happens with red lead to gate, black lead to source.
Also, the longer I keep the probes on the leads the more the meter will climb up
real slowly without ever seeming to stop. What's really strange to me is that... let's
say it starts at 1950, and I let it go until 1980...if I take the probes off and then
back on again, rather than starting back at 1950, it will continue from whatever point it
left off at previously.
The ohm reading was taken with my meter set on 400.
I'm sending you a PM with my address, however there really isn't a hurry because unfortunately, I didn't order ANY other transistors so I'll have to order Q2 anyway.
How many of Q2 or any others should I get and should I get another C4 cap or is that not necessary......also could you recommend a vendor for these...I would rather not use CP again. I haven't tried Mouser for these yet....that might be an option.
Mark, seriously....thank you VERY much for sending the diode. Let me know what I owe you!! Also, thank you very much for all your time, effort and patience with helping me out on this amp, I really do appreciate it!!
Anyway...the PM is on it's way......
Mouser is a viable choice because they have no minimum order, or fee for small orders, and will upon request ship out applicable orders First Class mail, which saves on shipping (2 buck versus 6 bucks UPS).
With the timing of the holiday weekend, realistically we will have a "parts hiatus" and I will try to have a list together by tonight or tomorrow so that the parts can hit the mail before the weekend.
WHEN you get the diodes, we will test the positive side by installing the diode, C4, and having Q1, Q3, Q5, Q7, Q9 & Q11 installed.
I have changed my intent (forget mouser for now), and I am sending you the following:
2x 6v 0.5 watt zener diodes
1x 47uF 25v Cap
1x 47uF 16v Cap
2x 2sd667 (Q1,Q2) 120v, 1 amp, 0.9 watt 140mhz npn transistor with ECB layout
2x 2sd756 (Q7,Q9) 120v, 0.05 amp, 0.75 watt 350mhz npn transistor with ECB layout
1x 2sb716 (Q3,Q4,Q8,Q10) 120v, 0.05 amp, 0.75 watt 150mhz PNP transistor with ECB layout
no jfets, the ones I have are only 30 volts..
sorry, I don't have many 2sb716's so I could only send one... (i'm a bit low on higher voltage pnp small signal transistors right now)
These extra parts should allow us to get a leg up on the problem. It could be instructive to test the other (nte replacement) jfet (out of circuit) to see how that responds to the tests.
I should have pressed harder for getting the replacement parts originally from mouser, as for the price, there would have been plenty of room for buying spares... offhand I would expect to pay less than a quarter apiece for them, the shipping would have been larger than the parts cost.
EDIT: (again...) It's on the way, my lettercarrier has it...
With the timing of the holiday weekend, realistically we will have a "parts hiatus" and I will try to have a list together by tonight or tomorrow so that the parts can hit the mail before the weekend.
WHEN you get the diodes, we will test the positive side by installing the diode, C4, and having Q1, Q3, Q5, Q7, Q9 & Q11 installed.
I have changed my intent (forget mouser for now), and I am sending you the following:
2x 6v 0.5 watt zener diodes
1x 47uF 25v Cap
1x 47uF 16v Cap
2x 2sd667 (Q1,Q2) 120v, 1 amp, 0.9 watt 140mhz npn transistor with ECB layout
2x 2sd756 (Q7,Q9) 120v, 0.05 amp, 0.75 watt 350mhz npn transistor with ECB layout
1x 2sb716 (Q3,Q4,Q8,Q10) 120v, 0.05 amp, 0.75 watt 150mhz PNP transistor with ECB layout
no jfets, the ones I have are only 30 volts..
sorry, I don't have many 2sb716's so I could only send one... (i'm a bit low on higher voltage pnp small signal transistors right now)
These extra parts should allow us to get a leg up on the problem. It could be instructive to test the other (nte replacement) jfet (out of circuit) to see how that responds to the tests.
I should have pressed harder for getting the replacement parts originally from mouser, as for the price, there would have been plenty of room for buying spares... offhand I would expect to pay less than a quarter apiece for them, the shipping would have been larger than the parts cost.
EDIT: (again...) It's on the way, my lettercarrier has it...
ehc68
My SX-1050
Mark, what can I say? Thank you, thank you, thank you!!:thmbsp: 
You are awesome brother!:thmbsp:
Again, let me know what I owe you. In addition to payment, I can send you all the GOOD transistors that don't get used after the amp is fixed. I get paid next Wednesday...(hopefully that will be ok)....just let me know.
Q1, Q3, Q5, Q9 and Q11 are what are currently soldered in the board. Do you want me to pull Q1, Q3 and Q9 again and replace them with what you send me?
If so, I'll start on it now and have it ready to go.
I'm getting ready to pull Q5 (the other jfet) and do a comparison.
You are awesome brother!:thmbsp:
Again, let me know what I owe you. In addition to payment, I can send you all the GOOD transistors that don't get used after the amp is fixed. I get paid next Wednesday...(hopefully that will be ok)....just let me know.
Q1, Q3, Q5, Q9 and Q11 are what are currently soldered in the board. Do you want me to pull Q1, Q3 and Q9 again and replace them with what you send me?
If so, I'll start on it now and have it ready to go.
I'm getting ready to pull Q5 (the other jfet) and do a comparison.
ehc68 said:Mark, what can I say? Thank you, thank you, thank you!!:thmbsp:
You are awesome brother!:thmbsp:
Again, let me know what I owe you. In addition to payment, I can send you all the GOOD transistors that don't get used after the amp is fixed. I get paid next Wednesday...(hopefully that will be ok)....just let me know.
Q1, Q3, Q5, Q9 and Q11 are what are currently soldered in the board. Do you want me to pull Q1, Q3 and Q9 again and replace them with what you send me?
If so, I'll start on it now and have it ready to go.
I'm getting ready to pull Q5 (the other jfet) and do a comparison.
wer're in no hurry, plus have fun....
The transistors are only intended to be replacements for any that we have already found bad, for example Q2....
no rush on any $$, my investment is stuff that was already here and a few postage stamps. wait until we're finished...
The magic thread disappearing thing has happened, so here's a re-hash (almost said recap!! )....
I'm still looking for another JFET replacement that is cheaper than the NTE...
I found some 50v JFETS at ampslab.com, BUT they only sell 20 of them for $20.
Let's get the two positive voltage regulators going first, and then take some voltage readings of Q5 in operation, we won't be able to get anything into the shipping pipeline until tuesday anyway.
Mouser did have one other, less expensive fet that looked like it would work, BUT they had no stock, and had a projected in-stock date of June 27....
I am investigating changing that jfet to a mosfet... but have no expectations of success, neither would I expect you to experiment with the changeover...
)....I'm still looking for another JFET replacement that is cheaper than the NTE...
I found some 50v JFETS at ampslab.com, BUT they only sell 20 of them for $20.
Let's get the two positive voltage regulators going first, and then take some voltage readings of Q5 in operation, we won't be able to get anything into the shipping pipeline until tuesday anyway.
Mouser did have one other, less expensive fet that looked like it would work, BUT they had no stock, and had a projected in-stock date of June 27....
I am investigating changing that jfet to a mosfet... but have no expectations of success, neither would I expect you to experiment with the changeover...
ruesselschorf
Well-Known Member
I hope you guys will come up with a working substitution for the 2SK34 in the SA-9800 power board. I tell you I tried a lot of substitutes I bought here in Germany none of them worked in that position.
Maybe Echowars can help, I remember, he had a similar problem with an SX-1980 ?
I endet up designing my own voltage regulators with 7824 and 7924 integrated voltage regulators plus zeners, for the +/-32V and +/- 52V supply.
Pioneer screwed up that power board in the first place. Early boards had 4 TO220 transistors with heatsink on that board you can still see the 'footprint' of 2 transistors on the board, because that was far too hot, they removed 2 transistors from the board and added two Heat and voltage dropping resistors on the chassis right behind/below the flouroscan display.
If you don't get the +/- 52Volt running, tell me, I can show you some dirty tricks !
Helmut
Maybe Echowars can help, I remember, he had a similar problem with an SX-1980 ?
I endet up designing my own voltage regulators with 7824 and 7924 integrated voltage regulators plus zeners, for the +/-32V and +/- 52V supply.
Pioneer screwed up that power board in the first place. Early boards had 4 TO220 transistors with heatsink on that board you can still see the 'footprint' of 2 transistors on the board, because that was far too hot, they removed 2 transistors from the board and added two Heat and voltage dropping resistors on the chassis right behind/below the flouroscan display.
If you don't get the +/- 52Volt running, tell me, I can show you some dirty tricks !
Helmut