thanks for a diagram ,that could certainly help 🙂
I look tonight for the correspondence of the transistors, I still work with world directories of transitors in paper books, they are very precise and reliable in the equivalences
I look tonight for the correspondence of the transistors, I still work with world directories of transitors in paper books, they are very precise and reliable in the equivalences
On the Drive board at locations TR 528 (2sc1953) and TR 526 (2sa914) I can obtain the following as substitutions, please could you tell me if they are ok?
KSC3503DS - Bipolar (BJT) Single Transistor, NPN, 300 V, 100 mA, 7 W, TO-225AA, Through Hole
KSA1381ESTU - Bipolar (BJT) Single Transistor, PNP, 300 V, 100 mA, 7 W, TO-225AA, Through Hole
KSC3503DS - Bipolar (BJT) Single Transistor, NPN, 300 V, 100 mA, 7 W, TO-225AA, Through Hole
KSA1381ESTU - Bipolar (BJT) Single Transistor, PNP, 300 V, 100 mA, 7 W, TO-225AA, Through Hole
Apologies, but just wanted to slightly edit post number 15 and couldn't figure out how to do it, so here's the correct version.
Thanks guys.Yes, Ian, fair review of the instrument.. and it’s very nicely priced too.
Huggygood, thanks for asking and, yes, looking again at the four 5W 0.47ohm emitter resistors one is open so have ordered a couple of replacements so that both channels match.
“have you checked TR 137 138 139 140”
TR137
2sc1213A(positioned back to front)
BE I
BC I
EB 618
CB 614
EC I
CE I
TR138
2sc1213A(positioned back to front)
BE I
BC I
EB 612
CB 612
EC I
CE I
TR 139
A708 13CCY
BE 846
BC 1296
EB 588
CB 626
EC 761
CE 626
TR 140
A708 13CCY
BE 669
BC 1143
EB 601
CB 590
EC 762
CE 562
Thanks to your recommendation to look more closely at the Drive Board I discovered something else!
R555,556 and R561,562 have had a previous repair.
2 photos attached below.
The SM say they should all be 1.5Kohms
In circuit they all read about 760 ohms, EXCEPT R555 which reads 1.5Kohms
Should I replace all of them?
And with just standard 250mW 1.5Kohm carbon film resistors?
"recheck also all of the A913 and C1913.”
Below are the in-circuit readings, please could you let me know if they look ok?
If they need replacement, please can you recommend what’s best?
TR 135
2sa913
BE 590
BC586
EB I
CB I
EC 506(climbs)
CE 1250(climbs)
TR 133
2scv1913
BE I
BC I
EB 576
CB 520 (climbs)
EC 1100 (climbs)
CE 525
TR 136
2sa913
BE 590
BC 584
EB 1960 (climbs to I)
CB I EC 524
CE 1300 (climbs)
The Drive board’s TR 525, 526, 527, 528 in circuit read:
Anything look suspicious?
TR 528
2sc1953
BE I
BC 1945
EB 689
CB 672
EC 1760 moving
CE I
TR526
2SA914
BE 674
BC641
EB I
CB I
EC I
CE 1822
TR 527
2sc1953
BE I
BC I
EB 689
CB 672
EC 1780 moving
CE I
TR525
2sa914
BE 690
BC 670
EB I
CB 1956
EC I
CE 1735
Thanks guys.Yes, Ian, fair review of the instrument.. and it’s very nicely priced too.
Huggygood, thanks for asking and, yes, looking again at the four 5W 0.47ohm emitter resistors one is open so have ordered a couple of replacements so that both channels match.
“have you checked TR 137 138 139 140”
TR137
2sc1213A(positioned back to front)
BE I
BC I
EB 618
CB 614
EC I
CE I
TR138
2sc1213A(positioned back to front)
BE I
BC I
EB 612
CB 612
EC I
CE I
TR 139
A708 13CCY
BE 846
BC 1296
EB 588
CB 626
EC 761
CE 626
TR 140
A708 13CCY
BE 669
BC 1143
EB 601
CB 590
EC 762
CE 562
Thanks to your recommendation to look more closely at the Drive Board I discovered something else!
R555,556 and R561,562 have had a previous repair.
2 photos attached below.
The SM say they should all be 1.5Kohms
In circuit they all read about 760 ohms, EXCEPT R555 which reads 1.5Kohms
Should I replace all of them?
And with just standard 250mW 1.5Kohm carbon film resistors?
"recheck also all of the A913 and C1913.”
Below are the in-circuit readings, please could you let me know if they look ok?
If they need replacement, please can you recommend what’s best?
TR 135
2sa913
BE 590
BC586
EB I
CB I
EC 506(climbs)
CE 1250(climbs)
TR 133
2scv1913
BE I
BC I
EB 576
CB 520 (climbs)
EC 1100 (climbs)
CE 525
TR 136
2sa913
BE 590
BC 584
EB 1960 (climbs to I)
CB I EC 524
CE 1300 (climbs)
The Drive board’s TR 525, 526, 527, 528 in circuit read:
Anything look suspicious?
TR 528
2sc1953
BE I
BC 1945
EB 689
CB 672
EC 1760 moving
CE I
TR526
2SA914
BE 674
BC641
EB I
CB I
EC I
CE 1822
TR 527
2sc1953
BE I
BC I
EB 689
CB 672
EC 1780 moving
CE I
TR525
2sa914
BE 690
BC 670
EB I
CB 1956
EC I
CE 1735
bc212L or 2n4061 are exactly the same as the SA561
2sa733 are an equivalent too but i don't know about the KSA.
you need at least a transistor tester if you want to work as it should.
try to find this one in uk .
Mega328 Transistor Tester LCR Capacitance ESR Meter PWM DIY TFT LCD Generator | eBay
And at TR 532 a replacement was made by someone.
They used a BC2121 3C. Is this ok, or what would be the best replacement?
They used a BC2121 3C. Is this ok, or what would be the best replacement?
I don't know the KSA / KSC families
you should find some info on this site
All Transistors. Datasheet. Cross Reference Search. Transistor Database.
you should find some info on this site
All Transistors. Datasheet. Cross Reference Search. Transistor Database.
what I can tell you is that this amp is treacherous. it is almost direct coupled, very little or no capacitor in the signal path, you have to be sure what you are doing before turning it back on .
Thanks, this has been a great help.
I'll fully check the other transistors and let you know how I get on as I think they could be very influential in the 'idle current non-adjustment' problem.
Hope your repairs have been going well.
"it's ok ,2sa561 = BC212L" this is great news, if it tests ok I guess that it can't be improved upon!
I'll fully check the other transistors and let you know how I get on as I think they could be very influential in the 'idle current non-adjustment' problem.
Hope your repairs have been going well.
"it's ok ,2sa561 = BC212L" this is great news, if it tests ok I guess that it can't be improved upon!
Thanks for the warning. Yes, this comment is made so often about this amp..
I'm grateful that it was at least 'functioning' when I started upon it.
It's very highly regarded though.. compared to a C4/M4 combo.. will be interesting to hear it working well if I can get it to that point..
Thanks again for the assistance.
I'm grateful that it was at least 'functioning' when I started upon it.
It's very highly regarded though.. compared to a C4/M4 combo.. will be interesting to hear it working well if I can get it to that point..
Thanks again for the assistance.
Open question to everyone..
On the Drive board I'm about to replace four 1.5Kohm resistors.
Does it matter whether I use metal film or carbon resistors?
Is one type better suited than another in this location?
R556, R562, R555,R561.
On the Drive board I'm about to replace four 1.5Kohm resistors.
Does it matter whether I use metal film or carbon resistors?
Is one type better suited than another in this location?
R556, R562, R555,R561.