If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140
I do not recognise the part numbers and it may be very difficult to find datasheets because at that time* it was common for larger product manufacturers have semiconductors custom labelled, mainly to prevent third parties from repairing or copying electronic designs.
* date code 7935 = week 35, 1979 (1974 was a very confusing year for TTL IC identification)
The actual transistors will rarely be custom design, just common transistors re-labeled.
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
does it matter ? I.E. are you fixing original equipment ? can you figure out the functional requirements from the circuit, then identify current transistors that will work ?
figuring out the transistor specs via part marking is the most difficult way for old stuff as previously stated.
Registered Member #62937
Joined: Wed Jun 06 2018, 08:20PM
Location:
Posts: 32
I bought a box of parts from ebay and these came with the box. I have no idea what they were used in. It is impossible for me to find out the specs any other way. The parts seem to be from RCA. I think I found the 3801 one too:
Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140
I have never even seen a berylium oxide TO-3 insulator - they were very rare, (although I have seen a few transistors that have BeO internally - usually r.f. power devices) Mica was the only common insulator of those times. (with a razor blade or sharp knife edge you can split mica into thinner sheets) ---------------------------- I doubt that the datasheet that you found is for your 380-2 transistor, as we did not have such good transistors back then ;) and NTE did not exist until 1989 ! ---------- I'd expect equivalents to 2N3055, 2N3773, 2N2955 and HOT/flyback transistors from TVs etc. The smaller TO-66 transistor may be 2N3054. I did not do TV repairs so no numbers come to mind, so you will need to do a little research. There could even be a 78xx type regulator in that lot. -------------------- So, as mentioned above, it is best not to use these transistors for a new design, or even an old design - as the transistors are very old. If you are building something new then use newer design/better transistors. If it is just for knowledge/experience/experimenting then go ahead, but do not expect too much performance from those transistors.
Registered Member #2463
Joined: Wed Nov 11 2009, 03:49AM
Location:
Posts: 1546
The warning about the BeO insulator is part of an instruction manual for equipment I currently own and use. Here is an E-Bay listing for the ultrasonic cleaner I have.
For $120 US you can buy it today.
For $19 US, digikey will sell you a new BeO TO-3 size insulator.
Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140
Well that is interesting, I have several TO3 insulators that I've always just called 'ceramic' It seems I may have BeO ceramic ... D'oh ! So it seems that possibly berylium causes memory and hair loss - or is that just age :)
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.