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 Post subject: Value of old transistors & other solid-state components?
PostPosted: Feb Fri 03, 2012 11:01 pm 
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I sometimes groan when people ask these questions, but I honestly have no idea whether this stuff is worth 20 cents or $200.

I have two parts bins with lots of older transistors and other solid state components (rectifiers, ICs, you name it) that I got as part of a lot purchase.

I rarely if ever work on solid state gear and I'd like to empty these bins for other components that I do use. (I want to sell the contents, in other words, not the bins themselves.)

I'll post these in the Classifieds, but the rules require that you state a price. Any ideas? Guesses . . . ?

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

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 Post subject: Re: Value of old transistors & other solid-state components?
PostPosted: Feb Sat 04, 2012 1:56 am 
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The ECG numbers are the same as the NTE numbers that distributors currently sell at ever increasing prices. Early PNP and NPN germanium transistors are always needed by people who collect and restore vintage transistor sets. Unfortunately, these can become leaky even if NOS so they need to be checked.

Dave


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 Post subject: Re: Value of old transistors & other solid-state components?
PostPosted: Feb Sat 04, 2012 2:19 am 
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Dave Doughty wrote:
The ECG numbers are the same as the NTE numbers that distributors currently sell at ever increasing prices. Early PNP and NPN germanium transistors are always needed by people who collect and restore vintage transistor sets. Unfortunately, these can become leaky even if NOS so they need to be checked.
Dave


As an aside and for what it's worth, despite some discouraging results reported by various people, the NTE replacements for the germaniums (generally NTE 160, NTE126, (RF/IF) NTE102a, and NTE158 (output/driver)) have worked dandy for me and at least as good as the 40-year-old NOS versions. The cost is somewhat high but I would rather pay $7 for a brand new one than $10-15 for an NOS Amperex or something, and then find it wasn't very good either. Truth be told, I DID get some NOS versions and half of them were either marginal or dead.

Someone can correct me, but for the RF transistors I would think that using them is no more likely to cause a failure than leaving them in the package. That is, using them in a radio doesn't "wear them out", the failures are mostly caused by age anyway. Probably a different story with the power transistors.

I appeared to have "won" the informal BCB DX "contest" a few months ago with a bone-stock Zenith Royal 1000d that had at least half the original transistors replaced with the NTE equivalents. And it seemed to work just fine - two stations within about half an hour that were something like 4000 miles apart with a stock radio and the internal loop means it must have been doing something well.

Bryant and Cones say they don't work as well, but unless somebody has a time machine and can compare the performance of new NTEs to NOS versions that *aren't* 40-50 years old, I can't see how that can be proven.

Brett


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 Post subject: Re: Value of old transistors & other solid-state components?
PostPosted: Feb Sat 04, 2012 5:20 am 
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Sell them as a batch to somebody who has a curve tracer and a bit of time. I have two curve tracers but little time. Or, maybe somebody near you could let you use their curve tracer?

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 Post subject: Re: Value of old transistors & other solid-state components?
PostPosted: Feb Sat 04, 2012 5:24 am 
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You didn't say if the items were NOS or not, but assuming that they are (and you have no blue CK722's, now a collector's item), it would be a perhaps tedious task, but see what places like Digikey and Mouser sell them for, and then under price them.

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 Post subject: Re: Value of old transistors & other solid-state components?
PostPosted: Feb Sat 04, 2012 7:13 am 
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Nearly all of them are in original envelopes & boxes. Making a list and looking up zillions of values sounds about as much fun as chewing tinfoil while shaving my head with a cheese grater, to quote Sam Malone. I guess I brought it on myself by wanting to make some practical use of these bins :)

Phil Nelson


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 Post subject: Re: Value of old transistors & other solid-state components?
PostPosted: Feb Sat 04, 2012 7:23 am 
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You can take the easy way out and sell them as a lot, but as you know, you won't get near as much as selling them individually, priced below what the big guys get.

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 Post subject: Re: Value of old transistors & other solid-state components?
PostPosted: Feb Sat 04, 2012 5:58 pm 
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Quote:
Someone can correct me, but for the RF transistors I would think that using them is no more likely to cause a failure than leaving them in the package. That is, using them in a radio doesn't "wear them out", the failures are mostly caused by age anyway. Probably a different story with the power transistors.


Based on 25 yrs in the semiconductor business...

1. "Using them" creates heat and leakage current. Heat eventually fatigues internal connections, but that may take decades. Heat also accelerates chemical changes due to contaminants trapped in the package during manufacturing. Back in the 50s and 60s "clean rooms" for assembly weren't nearly as clean as Intel has today. Applied voltage also accelerates ion migration from internal contaminants. Think of it as a long-term electro-plating process.

2. I used to sell diodes to Sylvania when they initiated the ECG line. Other companies got on the same bandwagon, but without Sylvania's quality control. Some companies used to buy our QC failures "by the pound." Their theory was that for the hobbyist market, room temp performance was good enough. We tested at 125 or 175C and rejected parts for leakage. Test them at room temp on a curve tracer, and they look fine. There were companies on Long Island that had rooms full of curve-tracers in an almost "sweat shop" environment, screening QC failure parts to find "good ones."

3. "Not using them" may be only slightly less risky in terms of long-term life. Depends how they were assembled. That said, I have lots of 40 and 50 year old semiconductors that work just fine. I wouldn't install any in a heart pacemaker, but for fixing a radio... why not?

As to value, old germanium stuff has to be worth something to restorers and collectors. I tried to sell a germanium NOS "door knob" power transistor on ARF and got no takers at $5. Logic ICs from the 70s can be had for pennies at flea markets in Silicon Valley. No one remembers what they were used for. Now, if someone has an NOS Intersil 8038 or MAX038, you would have my attention instantly! If you can't sell them as a lot, try breaking them up into similar types... say power transistors as one group... and put them up on ARF Classified.

Rich


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 Post subject: Re: Value of old transistors & other solid-state components?
PostPosted: Feb Sun 05, 2012 2:23 am 
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Over the last couple of years, I have been picking up whatever germanium stuff I can find. Especially if I can find it in the original package so I can add it to my display collection of older semiconductors and tubes.

Sometimes at the ham flea markets, one can get them pretty cheap. Other times not. :) If it cathes my eye though, I don't mind paying a reasonable amount if my budget at the time allows it.

I love going through stuff like that too! :D


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