Help identify another germanium

[skidmark]

Got an amp with what I'm sure has a blown output. Furthermore I think there are germaniums
Both are TO-3 case power transistors
Tested both with a FNIRDi transistor tester.
One seems to test ok
The other one test say 2 resistors. 31.5 and 57.5 ohms.

Both transistors have the numbers - 4045 / 6709

Meter diode test:
Alleged bad transistor
base/emitter pos-base - .750
base/emitter neg-base - .112

base/collector pos-base - .550
base/collector neg-base - .111

collector/emitter pos-collector - .380
collector/emitter neg-collector - .029


Alleged good transistor
base/emitter pos-base - open
base/emitter neg-base - .111

base/collector pos-base - open
base/collector neg-base - .109

collector/emitter pos-collector - .530
collector/emitter neg-collector - .039

Comments?

[The Dude]

What amp? Do you have a schematic? Are those measurements out of circuit?

[Jon Snell]

Germanium transistors age rapidly and are only good for up to 25years as a rule.
NOS germaniums are usually as usefull as a chocolate fire guard.
A photo may help identify it.

[skidmark]

Germanium transistors age rapidly and are only good for up to 25years as a rule.
NOS germaniums are usually as usefull as a chocolate fire guard.
A photo may help identify it.

Company looks like Signetics

[skidmark]

What amp? Do you have a schematic? Are those measurements out of circuit?

I have no idea who made the amp.
Yes those measurement are out of the circuit.
It's been many moons since I last test germaniums so my yard stick is fuzzy. Thats also why I'm seeking help.

Al

[mozz]

Germanium transistors age rapidly and are only good for up to 25years as a rule.
NOS germaniums are usually as usefull as a chocolate fire guard.
A photo may help identify it.

Nope, i have a few thousand germaniums US, JAPAN made in the 60's and a thousand Russian's made from the 60's to the 80's. Maybe 1 out of 50 is noisy but still works. Over 60 years old. Please show us a article or explicit testing of these bad at 25 years. Don't start rumors if you can't back it up because my personal experience is the total opposite.

[glebert]

Getting into a pissing match about germanium longevity isn't going to help the OP.

[J M Fahey]

Got an amp with what I'm sure has a blown output. Furthermore I think there are germaniums
Both are TO-3 case power transistors
Tested both with a FNIRDi transistor tester.
One seems to test ok
The other one test say 2 resistors. 31.5 and 57.5 ohms.

Both transistors have the numbers - 4045 / 6709

Meter diode test:
Alleged bad transistor
base/emitter pos-base - .750
base/emitter neg-base - .112

base/collector pos-base - .550
base/collector neg-base - .111

collector/emitter pos-collector - .380
collector/emitter neg-collector - .029


Alleged good transistor
base/emitter pos-base - open
base/emitter neg-base - .111

base/collector pos-base - open
base/collector neg-base - .109

collector/emitter pos-collector - .530
collector/emitter neg-collector - .039

Comments?

The good one measures like a PNP Germanium transistor.

Brand is probably Solitron, they were important back in the day.

Post trnsistor pictures but more important amp ones, so we may guess what you have there.

Also power supply voltages.

Does it have a driver transformer?

It *might* be converted to use PNP Silicon transistors but we need WAY more data

, i have a few thousand germaniums

Do you have TO3 ones?

[Jon Snell]

Nope, i have a few thousand germaniums US, JAPAN made in the 60's and a thousand Russian's made from the 60's to the 80's. Maybe 1 out of 50 is noisy but still works. Over 60 years old. Please show us a article or explicit testing of these bad at 25 years. Don't start rumors if you can't back it up because my personal experience is the total opposite.

https://www.sciencedirect.com/scienc...00936123002376
https://nepp.nasa.gov/whisker/anecdo...ransistors.pdf

There seems to be advice, contained in those articles, that refer to the manufacturing methods used.
If silver is no longer used in their production, the issue has been solved.

I repair many older trandidtorised amplifiers and most old germanium transistors I test and have to replace using silicon PNP types, rebiasing is usually a simple procedure, fixes the original issue of leaking germanium components.
Including Selenium rectifiers as well.

Even in modern BGA soldering, using Silver based solder. whiskers cause issues; Gaming consoles with the "red ring of death" and many LCD projectors suffer from early failures. Re heating the BGA chips will usually fix this for another 10 years.

It is a matter of trust. I wouldn't trust a 'germanium' device made in a country with no QC systems, personally.I would fit modern replacement.

Many 1N60's made in China are actually Shottky diodes, not germanuim at all!

There is plenty of documentaion regarding tin whiskers on many platforms. Take a look.

[mozz]

You painted a broad brush, AF114 is the tin whisker problem but that does not mean all germaniums have that problem. I stand by my experience that most all germanium transistors do not have a limited shelf or usage life. TO3 if over heated/overvoltage I'm sure they do go bad.

As to the original problem, it's a manufacturers number, so if no schematic or model number you would have to figure out what voltages/current it's run at and approx how many wattage to fit a replacement.

[mozz]

Getting into a pissing match about germanium longevity isn't going to help the OP.

Either is a post such as yours when it could have been a private message. I tried to answer above. When people paint a broad brush such as "all germanium are bad" i feel like i have to respond. You don't want any tech's to think they have to rip out any/all germanium that they come across during a repair. I'm sure the TO-3 outputs used in many 60's amplifiers could be replaced with a silicon but it may be above the guys pay grade to set the bias and make any mods needed to the amp. Maybe if he found a matched pair of old stock germaniums it would be easier to bias them and get it running again.Shooting blind with no model and/or schematic.

[J M Fahey]

. I wouldn't trust a 'germanium' device made in a country with no QC systems,

You always speak in riddles, which would that Country be?

[DrGonz78]

I actually am for removing germanium outputs and converting them to silicone. My thinking is more about improving upon the design of the amp and making it easier to service in the future. But sometimes I just want to hear what an old designed amp sounds like. So there are times I decided to search out old crusty germanium replacements. In my quests for these self destructive devices I have never purchased a bad one that didn’t work. I am sure I have just been lucky and I have a pretty good track record for hunting down obsolete parts.

[skidmark]

Ok gents, I've decided to bite the bullet and convert to silicon. I've never done this before. I'm quite capable of doing it, but with any new thing there's always the possibility of some
gotcha's out there lurking. So with that said could any one of you educate me. You do not have to dumb it down too much, I HOPE. I've read enough to know that one of the things
is changing the bias from .2 I think, to .5 to .6 volts, but that is about as far as I know. So with that, class is in session if one of ya don't mind teaching.

Al

[DrGonz78]

I have no idea who made the amp.

You always should include the community here in issues like this. Have you posted a picture of the amp in question? I’m sure someone will know what amp it is or not. Either way we could have known this or not a few posts ago. But we need a schematic to really be of any use immediately. No schematic. Then get there with the camera and take pictures of the boards and things. Especially the output section. Interstage transformer? What resistors are we gonna have to adjust? These are the only important things at this moment. Without more information we are in the dark.