I decided to try the old Dumont 274-A Oscillograph (I guess the word oscilloscope was not invented yet ) I got part of the lot I fetched earlier this week. The inside was kind of clean but was still waiting for an explosion when I plugged-in the beast. I was astonished to see that it was kind of working. Probably need a good recap though
Talking about caps I'm probably too young but it's the first time I see those brown capacitor in wax. They look like wine bottle cork.
For things like this I bought a cheap USB-to-GPIB converter:
Works fine under Linux as a serial device. Haven't done much with it, though. So I don't know if or how the more 'interesting' parts like SRQ are working.
Speaking of making cakes: here are some examples of my production (this is another hobby of mine)
And yes, I DO live southern of the river Main.
No, I don't. I'm not good enough for them. But that's okay, because important to me is that the people like my cakes.
My reward is looking on their happy faces.
Edit: Just for med: guess, what kind of cake this is:
I decided to try the old Dumont 274-A Oscillograph
YEA ME! Just won this fine example of a later HP 427A, looks to be in very good condition.
https://www.ebay.com/itm/Vtg-Hewlett-Packard-Voltmeter-427A-Volt-Meter-Tester-Excellent-Powers-Up-HP-/183787763383?_trksid=p2349526.m4383.l10137.c10&nordt=true&rt=nc&orig_cvip=true#viTabs_0
I decided to try the old Dumont 274-A Oscillograph (I guess the word oscilloscope was not invented yet ) I got part of the lot I fetched earlier this week. The inside was kind of clean but was still waiting for an explosion when I plugged-in the beast. I was astonished to see that it was kind of working. Probably need a good recap though
Talking about caps I'm probably too young but it's the first time I see those brown capacitor in wax. They look like wine bottle cork.Are you going to clean it up and get rid of the wax caps? Might not be the most useful scope by modern standards, but could still be a cool "conversation starter" in the lab.
Also interesting to contrast this "oscillograph" with the stuff Tektronix was making just a decade or two later and marvel about how fast 'scopes developed.
YEA ME! Just won this fine example of a later HP 427A, looks to be in very good condition.
https://www.ebay.com/itm/Vtg-Hewlett-Packard-Voltmeter-427A-Volt-Meter-Tester-Excellent-Powers-Up-HP-/183787763383?_trksid=p2349526.m4383.l10137.c10&nordt=true&rt=nc&orig_cvip=true#viTabs_0
Damn! There was a 475 on German eBay that I wanted. And (once more) simply forgot to bid! I would have paid quite a bit more than the winning did. Although he might have topped me anyway, that was a very good chance that I missed. I feel miserable now.
I decided to try the old Dumont 274-A Oscillograph (I guess the word oscilloscope was not invented yet ) I got part of the lot I fetched earlier this week. The inside was kind of clean but was still waiting for an explosion when I plugged-in the beast. I was astonished to see that it was kind of working. Probably need a good recap though
Talking about caps I'm probably too young but it's the first time I see those brown capacitor in wax. They look like wine bottle cork.Are you going to clean it up and get rid of the wax caps? Might not be the most useful scope by modern standards, but could still be a cool "conversation starter" in the lab.
Also interesting to contrast this "oscillograph" with the stuff Tektronix was making just a decade or two later and marvel about how fast 'scopes developed.
Judging by the type of vacuum tubes used......all octal types and using a later obsolete "80" type for the rectifiers....would place this scope late 1930's, early 1940's.
The non-linear sweep is definitely caused by a leaky cap in the sweep circuit. All those tubular caps, especially the brown wax ones, are no good, guaranteed. Although even when everything was up to snuff these old scopes weren't very linear.
https://www.oscilloscopemuseum.com/oscilloscope-dumont-274a-s1205.html
Looks like this site has some manuals.
That Dumont scope used a dead simple recurrent sweep circuit and that type of circuit was used in post WW2 "hobby" scopes for the TV repair market. Heath scopes used that type of circuit right up into the 1960's. You set your rough horizontal sweep then adjusted the fine horizontal until the sweep locked....or I should say...at least slowed down so you could view it. It never locked for long, they would slowly drift.
Tektronix developed the much superior triggered sweep which is standard today on all analog and digital scopes.
https://www.oscilloscopemuseum.com/oscilloscope-dumont-274a-s1205.html
Looks like this site has some manuals.
That site says it dates to 1948. I think it's earlier than that.
A little more cramped than the 19″ models, but mostly fine.
Solartron uses some novel scheme for interconnecting the boards. These contact combs (lacking a better word) can be slid out and back again. This, however, gets a bit tricky when you can't see the contacts, as this comb is easily tilted a bit and misses them. It also means that operating the instrument while the boards are separated (so you have easy access to the base PCB) is not possible.
Black Forest cake, of course. I was in the Black Forest a few years ago, watched a baker there make one with lots of kirschwasser and even more whipped cream. Then, I ate some of it. Yum!
Solartron uses some novel scheme for interconnecting the boards. These contact combs (lacking a better word) can be slid out and back again. This, however, gets a bit tricky when you can't see the contacts, as this comb is easily tilted a bit and misses them. It also means that operating the instrument while the boards are separated (so you have easy access to the base PCB) is not possible.
Solartron uses some novel scheme for interconnecting the boards. These contact combs (lacking a better word) can be slid out and back again. This, however, gets a bit tricky when you can't see the contacts, as this comb is easily tilted a bit and misses them. It also means that operating the instrument while the boards are separated (so you have easy access to the base PCB) is not possible.
The 7075 is worse
Imagine having the red plastic carrier between the circuit boards, and not being able to see between the boards without removing them from the case.
Separating the boards is easy, reassembling them requires some trial and error.
Now for a small relief.
Klein+Hummel Röhrenvoltmeter (VTVM) RV-12. According to radiomuseum.org it is of 1962 vintage.
Now for a small relief.
Klein+Hummel Röhrenvoltmeter (VTVM) RV-12. According to radiomuseum.org it is of 1962 vintage.
And you can tell where they got their inspiration. It's almost a direct copy of the Heath VTVM's of the same era.
Sounds more promising for low speed DC fans Still waiting on mine but I think it will be taking the scenic route via two states capitals due to it and my origin.
Playing amateur Ham today my little baofeng turned up - stock antenna is so I have used most of my coax test leads joined to get it up a small pole Hitting a repeater 30+km away so not terrible even with that dodge. Discone and a proper pole in the near future for this and the SDR playing.
And this slightly crusty PAT box I scored for not to much. Scrubbing brush and industrial detergent time.
edit: Photo of what is under the bonnet. ATMEGA84 based. Much safer to scrub the outer with the electrics out.
I decided to try the old Dumont 274-A Oscillograph (I guess the word oscilloscope was not invented yet ) I got part of the lot I fetched earlier this week. The inside was kind of clean but was still waiting for an explosion when I plugged-in the beast. I was astonished to see that it was kind of working. Probably need a good recap though
Talking about caps I'm probably too young but it's the first time I see those brown capacitor in wax. They look like wine bottle cork.
Are you going to clean it up and get rid of the wax caps? Might not be the most useful scope by modern standards, but could still be a cool "conversation starter" in the lab.
Also interesting to contrast this "oscillograph" with the stuff Tektronix was making just a decade or two later and marvel about how fast 'scopes developed.
Tuesday evening's find, from a trash barrel being used as storage for various types of electronics and cables.
Yes that's a Heath Voltage Reference Source from the M-E Lab Components series (Snippity) I will probably make sure it works, calibrate it, play with it a bit to see how accurate it is and then ask if anyone more interested in collecting Heath gear than me wants to buy it.
And how I came to to be introduced to the trash barrel, well that's a story for another evening.
Now for a small relief. Klein+Hummel Röhrenvoltmeter (VTVM) RV-12. According to radiomuseum.org it is of 1962 vintage.
Which company dealing with electronics did not offer their interpretation of the (presumably) same basic design?
Klein+Hummel, makers of studio and HiFi ecquipment, were assimilated in 2009 by Sennheiser, but they had and still have an excellent reputation.
You guessed right this time, again with the boring 10 V reference:
Note that the necessary 1 MΩ resistance is inserted. That looks rather good. (SNIP)
So you thought it was finally over? Nah, you were wrong. It ain't over 'till the fat lady sings!
And the saga continues ... ... with the Solartron 7050 and its lookalikes. The 2 of them are not exactly the same. Do you spot the difference?
(SNIP) This concludes the Solartron extravaganza. Now that the fat lady has done her part, the final curtain falls and I can go back to my lazy, slow pace.
Thanks all of you for watching and not complaining about all those pics.