There is a picture of the output transistors on page 1 of the thread if that helps.
Re-do an SA-6500ii?
- Thread starter Panamafred
- Start date
It does, a bit, (it confirmed no squeeze above the transistors) but I need to dig up some transistors from my "collection" : a batwing AND a to-3p and get the two together to compare. They are in a refrigerator sized stack of boxes that has to be unstacked to locate them. I would LOVE to get my hands on some baker's pan racks... I kick myself because, once, long ago, I had that opportunity.
BTW, see those white fabric covered wires between the output transistors in the picture? That fly from the board to small components mounted on the heat sink?
Those are the infamous thermal bias diodes.
Those are INCREDIBLY FRAGILE, they LOVE to break off flush where they enter the thermal diode.
When they do, and the power is turned on, they LOVE to make the amplifier go up in smoke. Can be quite violent. And destructive...
So do NOT bend those wires at all in their last 1/4 to 1/2 inch from the case!!
edit:
Here's what I was looking for: the sideways mount (granted it is a SA-7800, not a 6500ii
)....
The batwing transistors were used because of their greater heat transfer ability than a TO-220.
However the batwing case never gained wide usage and thus no modern replacements.
It didn't make sense to try to find rarer examples of recently developed TO-220's that ALMOST make the wattage requirements.
That would cause the amp to be limited from being "party cranked" without courting failure...
BTW, see those white fabric covered wires between the output transistors in the picture? That fly from the board to small components mounted on the heat sink?
Those are the infamous thermal bias diodes.
Those are INCREDIBLY FRAGILE, they LOVE to break off flush where they enter the thermal diode.
When they do, and the power is turned on, they LOVE to make the amplifier go up in smoke. Can be quite violent. And destructive...
So do NOT bend those wires at all in their last 1/4 to 1/2 inch from the case!!
edit:
Here's what I was looking for: the sideways mount (granted it is a SA-7800, not a 6500ii
)....The batwing transistors were used because of their greater heat transfer ability than a TO-220.
However the batwing case never gained wide usage and thus no modern replacements.
It didn't make sense to try to find rarer examples of recently developed TO-220's that ALMOST make the wattage requirements.
That would cause the amp to be limited from being "party cranked" without courting failure...
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Wow, that's a lot of info, thanks Mark. Looking forward to taking the next steps on this project. I will be aware of thermal bias diodes in the future.
Yo! Happy New Year Pio-nuts!
I still have this SA-6500ii looking sad in the basement. I gathered from other posts that MTF was out for a while, GLAD HE'S back! SO here I am grovelling for some help on figuring out a list of transistors for this little guy. Thanks in advance!
I still have this SA-6500ii looking sad in the basement. I gathered from other posts that MTF was out for a while, GLAD HE'S back! SO here I am grovelling for some help on figuring out a list of transistors for this little guy. Thanks in advance!
Last ditch grovel!
Hope everyone is staying warm -30 wind chills in WI today
:stupid:
Hope everyone is staying warm -30 wind chills in WI today
:stupid:
It's called a bump, not groveling...
and an hour later... :
awk-083 q1 ta7136 eq amp
awk-083 q2 ta7136 eq amp
awk-083 q3 2sa640 50v 0.05a 0.25w 450hfe 100mhz to-92 control amp (flat/tone) 512-KSA992FBU
awk-083 q4 2sa640 50v 0.05a 0.25w 450hfe 100mhz to-92 control amp (flat/tone) 512-KSA992FBU
awk-083 q5 2sc1222 45v 0.05a 0.25w 450hfe 100mhz to-92 control amp (flat/tone) 512-KSC1845FTA
awk-083 q6 2sc1222 45v 0.05a 0.25w 450hfe 100mhz to-92 control amp (flat/tone) 512-KSC1845FTA
awk-083 q7 2sa640 50v 0.05a 0.25w 450hfe 100mhz to-92 input diff 512-KSA992FBU
awk-083 q8 2sa640 50v 0.05a 0.25w 450hfe 100mhz to-92 input diff 512-KSA992FBU
awk-083 q9 2sa640 50v 0.05a 0.25w 450hfe 100mhz to-92 input diff 512-KSA992FBU
awk-083 q10 2sa640 50v 0.05a 0.25w 450hfe 100mhz to-92 input diff 512-KSA992FBU
awk-083 q11 2sc1438 150v 0.05a 0.5w 150hfe 130mhz to-92 vas 512-KSC1845FTA
awk-083 q12 2sc1438 150v 0.05a 0.5w 150hfe 130mhz to-92 vas 512-KSC1845FTA
awk-083 q13 2sa850 100v 0.5a 0.8w 300hfe 130mhz to-92 driver 512-KSA1013YBU
awk-083 q14 2sa850 100v 0.5a 0.8w 300hfe 130mhz to-92 driver 512-KSA1013YBU
awk-083 q15 2sc1735 100v 0.5a 0.8w 300hfe 130mhz to-92 driver 512-KSC2383YTA
awk-083 q16 2sc1735 100v 0.5a 0.8w 300hfe 130mhz to-92 driver 512-KSC2383YTA
awk-083 q17 2sb616 100v 5a 60w 80hfe 22mhz batw power output 512-TIP42C
awk-083 q18 2sb616 100v 5a 60w 80hfe 22mhz batw power output 512-TIP42C
awk-083 q19 2sd586 100v 5a 60w 80hfe 22mhz batw power output 512-TIP41C
awk-083 q20 2sd586 100v 5a 60w 80hfe 22mhz batw power output 512-TIP41C
awk-083 q21 2sa777 80v 0.5a 0.75w 100-220hfe 130mhz to-92L switched current source? 512-KSA1013YBU
awk-083 q22 2sa777 80v 0.5a 0.75w 100-220hfe 130mhz to-92L switched current source? 512-KSA1013YBU
awk-083 q23 2sc1318 50v 0.5a 0.625w 300hfe 200mhz to-92 '+34v regulator 512-KSC2690AYS
awk-083 q24 2sc945 50v 0.15a 0.25w 40-700hfe 300mhz to-92 blow fuse protect 512-KSC1845FTA
awk-083 q25 2sa733 50v 0.15a 0.25w 40-700hfe 180mhz to-92 blow fuse protect 512-KSA992FBU
awk-083 q26 2sc945 50v 0.15a 0.25w 40-700hfe 300mhz to-92 current source master switch 512-KSC1845FTA
awk-083 q27 2sc1318 50v 0.5a 0.625w 300hfe 200mhz to-92 '+34v regulator shutdown 512-KSC2383YTA
awk-083 d14 eqa01-35r 35v zener diode uh oh, need a string of 2
and an hour later... :
awk-083 q1 ta7136 eq amp
awk-083 q2 ta7136 eq amp
awk-083 q3 2sa640 50v 0.05a 0.25w 450hfe 100mhz to-92 control amp (flat/tone) 512-KSA992FBU
awk-083 q4 2sa640 50v 0.05a 0.25w 450hfe 100mhz to-92 control amp (flat/tone) 512-KSA992FBU
awk-083 q5 2sc1222 45v 0.05a 0.25w 450hfe 100mhz to-92 control amp (flat/tone) 512-KSC1845FTA
awk-083 q6 2sc1222 45v 0.05a 0.25w 450hfe 100mhz to-92 control amp (flat/tone) 512-KSC1845FTA
awk-083 q7 2sa640 50v 0.05a 0.25w 450hfe 100mhz to-92 input diff 512-KSA992FBU
awk-083 q8 2sa640 50v 0.05a 0.25w 450hfe 100mhz to-92 input diff 512-KSA992FBU
awk-083 q9 2sa640 50v 0.05a 0.25w 450hfe 100mhz to-92 input diff 512-KSA992FBU
awk-083 q10 2sa640 50v 0.05a 0.25w 450hfe 100mhz to-92 input diff 512-KSA992FBU
awk-083 q11 2sc1438 150v 0.05a 0.5w 150hfe 130mhz to-92 vas 512-KSC1845FTA
awk-083 q12 2sc1438 150v 0.05a 0.5w 150hfe 130mhz to-92 vas 512-KSC1845FTA
awk-083 q13 2sa850 100v 0.5a 0.8w 300hfe 130mhz to-92 driver 512-KSA1013YBU
awk-083 q14 2sa850 100v 0.5a 0.8w 300hfe 130mhz to-92 driver 512-KSA1013YBU
awk-083 q15 2sc1735 100v 0.5a 0.8w 300hfe 130mhz to-92 driver 512-KSC2383YTA
awk-083 q16 2sc1735 100v 0.5a 0.8w 300hfe 130mhz to-92 driver 512-KSC2383YTA
awk-083 q17 2sb616 100v 5a 60w 80hfe 22mhz batw power output 512-TIP42C
awk-083 q18 2sb616 100v 5a 60w 80hfe 22mhz batw power output 512-TIP42C
awk-083 q19 2sd586 100v 5a 60w 80hfe 22mhz batw power output 512-TIP41C
awk-083 q20 2sd586 100v 5a 60w 80hfe 22mhz batw power output 512-TIP41C
awk-083 q21 2sa777 80v 0.5a 0.75w 100-220hfe 130mhz to-92L switched current source? 512-KSA1013YBU
awk-083 q22 2sa777 80v 0.5a 0.75w 100-220hfe 130mhz to-92L switched current source? 512-KSA1013YBU
awk-083 q23 2sc1318 50v 0.5a 0.625w 300hfe 200mhz to-92 '+34v regulator 512-KSC2690AYS
awk-083 q24 2sc945 50v 0.15a 0.25w 40-700hfe 300mhz to-92 blow fuse protect 512-KSC1845FTA
awk-083 q25 2sa733 50v 0.15a 0.25w 40-700hfe 180mhz to-92 blow fuse protect 512-KSA992FBU
awk-083 q26 2sc945 50v 0.15a 0.25w 40-700hfe 300mhz to-92 current source master switch 512-KSC1845FTA
awk-083 q27 2sc1318 50v 0.5a 0.625w 300hfe 200mhz to-92 '+34v regulator shutdown 512-KSC2383YTA
awk-083 d14 eqa01-35r 35v zener diode uh oh, need a string of 2
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Mark, thank you so much! Can't believe how much help I've received from you. can I buy you a can of Faderlube or something? Really appreciate it.
I'm Having trouble tracking down these parts on Mouser:
awk-083 q1 ta7136 eq amp
awk-083 q2 ta7136 eq amp
awk-083 d14 eqa01-35r 35v zener diode
Thanks again!
I'm Having trouble tracking down these parts on Mouser:
awk-083 q1 ta7136 eq amp
awk-083 q2 ta7136 eq amp
awk-083 d14 eqa01-35r 35v zener diode
Thanks again!
of COURSE you are having trouble... ta7136is no longer made and the ones in there should be OK. I did NOT give parts numbers for the parts that shouldn't be replaced.
the 35v zener has only 33 and 36 volt zeners in leaded packages. PLUS the SX-1980 mod says use a 17 and an 18 v zener in series instead of a 35v zener.
512-1N5257B Fairchild 33 V, 0.5W zener
512-1N5258B Fairchild 36 V, 0.5W Zener
get these:
512-1N5247B Fairchild 17 V, 0.5W Zener
512-1N5248B Fairchild 18 V, 0.5W Zener
and put them in series, anode to cathode...
talk to me about it when ready, don't try to wing it...
Thanks Mark!
This thread will probably resurface in a week or so once the order shows up and I get lost in the weeds.
You're the best man, I really appreciate it.
Thanks again!
This thread will probably resurface in a week or so once the order shows up and I get lost in the weeds.
You're the best man, I really appreciate it.
Thanks again!
Alright, I've run into my first road block here. My printer is kind of crumby and on the schematic it looked like D15 was Q15, I removed it and got distracted reading data sheets and then when I went to replace it I notice the PCB isn't marked ECB like I expected!
Instead, it reads AGC and there is a little rectangle with a line running through it. Is this an "automatic gain control diode"? It looks like a transistor! Well, now the problem is I don't know which way it goes back in. There are 2 ways it could go and I don't much feel like trial and error with $50 invested in parts and the time everyone has invested. Is there a way to figure out which leg goes where with a DMM?
Instead, it reads AGC and there is a little rectangle with a line running through it. Is this an "automatic gain control diode"? It looks like a transistor! Well, now the problem is I don't know which way it goes back in. There are 2 ways it could go and I don't much feel like trial and error with $50 invested in parts and the time everyone has invested. Is there a way to figure out which leg goes where with a DMM?
Aloha Pio - Nuts! Greetings from my basement! Replacement of transistors is going well despite beginning an 18 credit college semester 2 weeks ago. Greatly aided by a hoard of New Age-y cassettes un-earthed this week!
This has been a fun unit to work on, but now, as per Mark's instructions I am requesting help on the Zener diodes. I have also yet to resolve my problem with D15 in the above post, have done a little research, and as per: http://www.datasheetarchive.com/dlmain/Datasheets-38/DSA-754653.pdf can determine which pin is T1, T2 and G, however it is unclear to me how that corresponds to AGC.
That being said I mis-ordered and got 4 PNP outputs and will have to put in another order to Mouser this week. :withstpd:
Onwards, and upwards!
This has been a fun unit to work on, but now, as per Mark's instructions I am requesting help on the Zener diodes. I have also yet to resolve my problem with D15 in the above post, have done a little research, and as per: http://www.datasheetarchive.com/dlmain/Datasheets-38/DSA-754653.pdf can determine which pin is T1, T2 and G, however it is unclear to me how that corresponds to AGC.
That being said I mis-ordered and got 4 PNP outputs and will have to put in another order to Mouser this week. :withstpd:
Onwards, and upwards!
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:nutz:
Bump!
Bump!
Just curious, did this turn into a full on rebuild? I have a 6500II with a channel out (can't recall which now) AND a 7500II with a channel acting up.
If this is a rebuild I'm thinking that may be the best route for me. There were mods done (prior owner) to the main logic that I know aren't factory.
If this is a rebuild I'm thinking that may be the best route for me. There were mods done (prior owner) to the main logic that I know aren't factory.
It was supposed to just be a re-cap, but I didn't insulate my probes properly and it turned in a full re-build!
:nutz:
Bump!
Bump!
For now you can do without that device, it is a "triac" which is a type of bidirectional silicon controlled rectifier.
It's SOLE purpose is to POP the MAIN fuse in case of a protection fault. Since we are watching the unit during troubleshooting, that isn't necessary - to prevent burning doen the house - they were too cheap or something to put in a protection relay.
AGC is a hold over from the " Silicon Controlled Rectifier (SCR)"
A anode
G gate
C cathode
where the gate voltage is raised over the cathode's voltage, which causes the current to flow from the anode to the cathode just like a diode.
In an SCR the current continues to flow forever - or until the anode voltage drops below the conduction threshold as referenced to the cathode.
Now, a TRIAC is a bi-directional SCR.
I DON'T know (right now) how the A and C relate to the t1 and t2 exactly - don't have time to dig deep, BUT:
t1 should go to the ground which is probably cathode - c
t2 should go to the main cap which is probably anode - a
g goes to g - bet on that...
but like I said, DON'T put it in, it will operate FINE without it.
You got a RARE interruption on the task (non-electronic) that is consuming my time almost exclusively right now. Look back at exactly how many posts I have made recently...
It's SOLE purpose is to POP the MAIN fuse in case of a protection fault. Since we are watching the unit during troubleshooting, that isn't necessary - to prevent burning doen the house - they were too cheap or something to put in a protection relay.
AGC is a hold over from the " Silicon Controlled Rectifier (SCR)"
A anode
G gate
C cathode
where the gate voltage is raised over the cathode's voltage, which causes the current to flow from the anode to the cathode just like a diode.
In an SCR the current continues to flow forever - or until the anode voltage drops below the conduction threshold as referenced to the cathode.
Now, a TRIAC is a bi-directional SCR.
I DON'T know (right now) how the A and C relate to the t1 and t2 exactly - don't have time to dig deep, BUT:
t1 should go to the ground which is probably cathode - c
t2 should go to the main cap which is probably anode - a
g goes to g - bet on that...
but like I said, DON'T put it in, it will operate FINE without it.
You got a RARE interruption on the task (non-electronic) that is consuming my time almost exclusively right now. Look back at exactly how many posts I have made recently...
I have a post on a 7500 II and wondering if the AGC you mention might be the issue with my amp. Thoughts?
I'd say that this absolutely has nothing to do with what's going on with your 7500.
This thread will hopefully prove helpful when I begin work on my 6500 II. I'd like to get one of these buggers working again.
I'd say it will be! Got the whole list of caps and transistors here.
Mark! I hope whatever is keeping you from the board is something good, wishing you the best. I'm pretty busy myself with school and just got the "you don't spend enough time with me" talk from the wife. Am in no hurry to finish here and I appreciate the continued support. I will:
1. Pull D15
2. Wait for your guidance on replacing the one zener diodes with the two
3. Not plug the thing in!
God bless, thanks again!
