700B blew one Right channel 5A supply fuse

[laatsch55]

Big caps for emphasis, wasn't really screaming , not a screamer...

 

[62vauxhall]

I have not been completely successful finding data sheets - T1S93 has eluded me.

Not even sure I comprehend what I'm looking at. Some show a pinout indentifying legs as E-B-C and some do not showing 1-2-3 with a table that includes E-B-C as well as other designations. Maybe this is for the benefit of different countries?

In some cases, it's not clear to me whether the diagram is a top view or a bottom view.

If nothing else, but excluding T1S93, I believe I learned which ones are NPN and which are PNP:
T1S-97 - NPN
T1S-93 - unknown
MPSA93 - PNP
2N3439 - NPN
2N5416 - PNP
2N1304 - NPN
2N1304 - PNP

For consistency, I view the transistors with the legs pointing towards me and flat side down for the small transistors - centre leg at top for the round metal ones.

With that in mind (and I could be completely wrong about this) E always seems to be on the left, B in the middle and C on the right. I thought E & C would be switched depending if NPN or PNP.

I thought there must be a way to use this DMM to determine what legs are E,B & C but have not found a method yet that I understand. One seemed concise at first glance but was gibbersh during a closer read. Either that or I'm brain dead from trying to suss this out.

Until I get that straight, I'm not yet going to try figuring out which legs go in what holes.

Will give it rest for now and come back later when my head clears.

 

[laatsch55]

When speaking of E-B-C, or such, it's a;lways referred to with a certain orientation. Around here, it is with the flat facing you and the legs down. the TO-39's have the same pinouts, don't sweat those. The TIS-97's, and TIS-93's you have are Fairchild Semiconductor devices and the pinots are direct from their website...

TIS-97 with orientation stated above---Collector --Base--Emitter
TIS-93"""" """"""""""""""""""""""""'---Same
MPSA 93--'''-----------'''----------------Emitter ---Base---Collector

 

[laatsch55]

NPN, or PNP does not determine pinouts, either can have a multitude of pinouts. There is a way to determine what pins are what but it's rather involved and takes a pretty good meter. Have you identified all transistors now?

 

[laatsch55]

You are showing ...
T -one-S they are T-eye-S

 

[laatsch55]

Gary, you're being awfully quiet...what can I do to help??

 

[62vauxhall]

Took a break for a couple of hours but did spend more time on the board. So far I've only replaced Q1 through 4 but it's a start. Those tracings can lift awful easy.

After taking off the old transistors, I could see they had in very small print, the leg markings which certainly helped. Only hope the letters E-B-CK didn't mean something else. I did need to bend the centre leg on some to agree with the description you sent.

Also earlier, you said the flat heatsinks were for Q3 & Q4. A total of 4 transistors but there were only 2 heatsinks. I can drive to the electronics shop tomorrow and get a couple more so it's no biggie.

 

[laatsch55]

Q4 is the only one that needs the flat heatsink. Could you post a pic of the installed Q1-Q4's and I'll crosscheck with my 14 a board here?

 

[laatsch55]

Those electrolytic caps I sent, some will not fit the olf lead spacing. In that case we rebend the new one to fit....like so....start by bending one lead in the diection it needs to go , then bend down where it matches the board holes....

 

[62vauxhall]

Thanks for the heads up with the cap leads, I'll bend accordingly.

One of your e-mails read "Q3,Q4 get the small, flat heatsink" so I assumed (god I do that a lot) that 4 were needed.

You sent three brown poly film caps. Where do those go?

Following are pics of Q1-Q4 that I installed using the Layout Diagram to identify. Q1 & Q2 are TIS-97 - Q3 are TIS-93 and Q4 are MPSA93

 

[Gepetto]

When speaking of E-B-C, or such, it's a;lways referred to with a certain orientation. Around here, it is with the flat facing you and the legs down. the TO-39's have the same pinouts, don't sweat those. The TIS-97's, and TIS-93's you have are Fairchild Semiconductor devices and the pinots are direct from their website...

TIS-97 with orientation stated above---Collector --Base--Emitter
TIS-93"""" """"""""""""""""""""""""'---Same
MPSA 93--'''-----------'''----------------Emitter ---Base---Collector

The MPS and most other TO-92 devices follow the industry convention of E-B-C from left to right, flat facing you, legs down.

The TIS devices followed some early, proprietary TI convention that never took hold.

 

[Gepetto]

Thanks for the heads up with the cap leads, I'll bend accordingly.

One of your e-mails read "Q3,Q4 get the small, flat heatsink" so I assumed (god I do that a lot) that 4 were needed.

You sent three brown poly film caps. Where do those go?

Following are pics of Q1-Q4 that I installed using the Layout Diagram to identify. Q1 & Q2 are TIS-97 - Q3 are TIS-93 and Q4 are MPSA93

View attachment 14269 View attachment 14270

What's up with all the other flying connections that I see going on?

 

[laatsch55]

The .o1uf/400 volt go on the 4 legs of the bridge rectifier as switching noise snubbers. Should have been 4 of them...

 

[laatsch55]

I've seen that a lot Joe. The only thing I can figure is they couldn't get the value resistor they needed so they paralled/seriesed up what they needed....

 

[62vauxhall]

What's up with all the other flying connections that I see going on?

Can't say for sure, not my doing.

I've had the amp since 1990 or so and in that time, has been to the shop 4 times. Those connections were either made on one of those occasions or before the amp came into my possession.

 

[62vauxhall]

The .o1uf/400 volt go on the 4 legs of the bridge rectifier as switching noise snubbers. Should have been 4 of them...

Sorry, yes there are four. One was astray in the bottom of my parts box.

 

[laatsch55]

I'll post a pic of how they should go.

 

[laatsch55]

Here ya go...

 

[laatsch55]

Gary, Q1-Q4 look correct. On the schematic you'll see Q1,Q2 share a common point with their emitters, same with Q3,Q4, and you have achieved that...

 

[62vauxhall]

Here ya go...

Doesn't look like you soldered those capacitors in place, is that yet to come or intentional? I used solder on mine.