Vintage test equipment - Page 1
Forum section: electronics / testgear

author: Matt Hatter
author_rank: Contributor
timestamp: July 28, 2017, 03:11:39 am
content: Alright... Where to start. Well, I'm looking at purchasing some old test equipment, and found a local guy selling his dad's old equipment (His dad was a TV repairman during the 60's). He has several O-scopes, a TV alignment generator, RF-AF TV Marker Generator, a Heathkit VTVM model V-6, a Navy surplus audio generator, a Resistance Capacitance Comparator, and about 50-60 odd tubes (most new but have been sitting and need testing). I'm fascinated with old analogue tech, and would love to add these to the bench, as I currently don't have an Oscilloscope. I don't mind some restorative work, but as I've never delt with these scopes or the old TV equipment I don't know if these are worth my time, or money.The stars of the show here (for me at least) are the two Heathkit O-scopes dating from the 60's. They turn on and display, but will obviously need a recap and some of the old resistors tested and replaced. Pictures below.Tv alignment generatorResistance Capacitance ComparatorHeathkit VTVM model V-6Audio Generator (I believe)He is asking $100 for the lot, which seems reasonable, however given my inexperience I'd rather deffer to you all. Thanks!

author: WastelandTek
author_rank: Frequent Contributor
timestamp: July 28, 2017, 04:11:44 am
content: Go binge watch Mr. Carlson before you plug any more of that stuff in K?

author: CatalinaWOW
author_rank: Super Contributor
timestamp: July 28, 2017, 04:16:20 am
content: You can probably get your $100 bucks back by reselling the tubes. Most will be slow movers but I am sure that a quarter of them will be things that move to audiophiles and other current users of tubes, and will go for several dollars each.The scopes will have extremely low bandwidth by today's standards - a couple of megahertz at most. That still leaves lots of neat stuff you can do with them, but not looking at the clocks on your Arduino or any other piece of digital gear made since the early 70s.The VTVM was a wonder in its day - a high impedance meter hooray, but is in no way comparable to DMMs that can be had for under $25 today.Similar arguments apply to all of this, so you will have to value it as a collector, or have specific interests that lie within the capabilities of this equipment. So no the decision is back on you.

author: Electro Detective
author_rank: Super Contributor
timestamp: July 28, 2017, 06:13:28 am
content: Quote from: WastelandTek on July 28, 2017, 04:11:44 amMr Carlson's Lab rules!!!www.youtube.com/user/MrCarlsonsLab/videos

author: Unknown
author_rank: Unknown
timestamp: July 28, 2017, 06:16:47 am
content: Quote from: CatalinaWOW on July 28, 2017, 04:16:20 amThe only sensible argument I've heard for using a VTVM these days is that the probe tip resistor provides a degree of isolation from the probe cable, minimising loading/detuning of the circuit under test. But it's easy enough to DIY a basic resistor probe, and for a typical DMM with >10M? input impedance it'll only add a few % error.(& if you really need the accuracy, you can work out your own compensation table just like a real VTVM probe...)

author: Robaroni
author_rank: Frequent Contributor
timestamp: July 28, 2017, 12:06:13 pm
content: Matt,As a kid I worked in a TV & Radio repair shop. Those VTVMs were our main trouble shooting instrument. I still have a really nice looking one in the basement (or as my wife calls it the 'Robsonian')In the early 70's I built one of those Heathkit scopes and had a couple of those gen sets too. I still have the IG-18 Audio Generator but my Agilent AWB has pretty much replaced it.Honestly, new equipment is so good that even cheap stuff today is way better but just seeing that old stuff really brings back the memories and fun I had as a teen in the 60's.Have a ball!

author: JLNY
author_rank: Regular Contributor
timestamp: July 28, 2017, 12:12:13 pm
content: Would this be intended as your daily-driver test gear?I mean, I'm all for fixing up and using vintage test gear if you think the capabilities will be sufficient for the kind of testing you expect to do, but in this case I fear the capabilities of this gear may leave you severely limited and would be cumbersome to use, as others have pointed out. $100 is a fair price, but some of these items are approaching an age that they might be better sold as collectibles rather than being used for testing.

author: Robaroni
author_rank: Frequent Contributor
timestamp: July 28, 2017, 12:24:18 pm
content: Quote from: JLNY on July 28, 2017, 12:12:13 pmDepends what you're working on, if you fix old tube audio or HAM stuff they'll probably be fine. Carlson seems to do OK with them. A good tech can do a lot with a VTVM, they were the mainstay for trouble shooting for decades.

author: Matt Hatter
author_rank: Contributor
timestamp: July 28, 2017, 12:25:09 pm
content: Quote from: JLNY on July 28, 2017, 12:12:13 pmTemporarily, yes. I'm currently designing a benchtop powersupply that will take over, I have a pretty decent DMM already, but for the time being, I figured an old 5 MHz scope of two is better than no scope at all. I was also wondering if I could modify any of the other pieces of equipment to serve alternate purposes. With not a lot of money to throw around, are there better options for similar cost that I'm neglecting?

author: Robaroni
author_rank: Frequent Contributor
timestamp: July 28, 2017, 12:36:24 pm
content: Matt,I see you're in the USA, PM me and I'll send you some test equipment to help you get going for free!Rob

author: bd139
author_rank: Super Contributor
timestamp: July 28, 2017, 12:43:16 pm
content: That's the best optionTBH I'd skip that lot for $100 entirely myself.It's mostly Heathkit stuff so you really never know what you're going to get. A non professional built it. Sometimes you get good ones where people have taken time and pride. On top of that, the scopes in that lot aren't anywhere even close to a usable scope by even 1980s standards. For $100 you could land yourself a cheap Chinese supply and an 1980s analogue scope and be better off.That VTVM is probably a nightmare. There's a C battery in there that has probably leaked. On top of that, if it's not been modified, the chassis is earthed so you can't make floating measurements without modifying it.Really I paid (converting from UK money), $30 for my Fluke 8600A, $40 for my TTI PL310 power supply and $30 for my Philips 50MHz scope. You could do so much better for $100.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: July 29, 2017, 02:02:48 am
content: I detect the signs of love in your response. There is no way the scopes are 5 MHz bandwidth. I can't get the model numbers off of the pictures, but the horizontal sweep frequency (frequency!) knobs tell the story. Highest frequencies are 100 kHz meaning bandwidth is at best in the 1 MHz neighborhood.You will be much happier going elsewhere for daily driver instruments. But they could easily provide $100 of fun.

author: jakeisprobably
author_rank: Regular Contributor
timestamp: July 29, 2017, 03:08:32 am
content: Mr Carlson's 1hr 42min restoration of and "Why you should own a VTVM."https://youtu.be/GR3rR7tc30YJake :-)BTW. I picked up a Rigol digital scope on Craigslist for a bill. I'd honestly recommend that route for the same amount of money. Sorting out old stuff isn't fun. I have had two old programmable power supplies from the late 80's sitting on my shelf for over a year. As a beginner myself I can say investing in the best possible tools is about the smartest path you can take.

author: med6753
author_rank: Super Contributor
timestamp: July 29, 2017, 08:06:17 am
content: The 2 Heathkit scopes and the VTVM are much older than the 1960's. They pre-date 1955 when Heath went from beige paint to grey paint. Although the 2nd scope is grey paint I'll bet it's model number is earlier than the O-10 which was their first 5 MHz scope which DID last with updates into the 1960's.I have a V-5 VTVM which is similar to that V-6 except it does not have a 1.5 volt range. The lowest it goes is 3 volts. Mine has been totally rebuilt with new caps and carbon resistors and I eliminated the selenium rectifier in the B+ circuit. Those scopes are full of wax capacitors which will need to be replaced. And that's just a beginning. A lot of the carbon resistors will be out of spec too. Not trying to discourage you. They CAN be restored but it will be a long term project.

author: bd139
author_rank: Super Contributor
timestamp: July 29, 2017, 09:29:51 am
content: Yeah watch out for the selenium rectifiers. You haven't lived until you've smelled one of them going bad. I plugged in a valve radio chassis when I was a kid and one went up in my face. Couldn't get the smell out of my hair for days. A cross between dead things and garlic.Quote from: jakeisprobably on July 29, 2017, 03:08:32 amI work on a similar principle of that I purchase the best tools possible that are broken and fix them. Everything I've bought in the last 20 years has been "spares/repair" and has required some research and work to get it going again. It's a good education.Incidentally if anyone likes VTVMs but doesn't want the hassle of high voltage, horrible old rancid parts and the risk of the device being constructed by a moron, look in the direction of Hewlett Packard's 427A voltmeter. It's a rather nice FET based voltmeter and has considerably lower ranges than the VTVMs do which make it perfectly suitable for more modern work. I use mine regularly.

author: ebastler
author_rank: Super Contributor
timestamp: July 29, 2017, 08:53:20 pm
content: Quote from: CatalinaWOW on July 29, 2017, 02:02:48 am+1. There are good reasons for liking and buying these vintage scopes -- learning about old technology, just liking the looks, knowing the instruments' prior owner and history... But for actual use, the price/benefit ratio just does not justify the purchase.So you will need to buy the old onesanda more modern scope!Time to start negotiating on the price.

author: JohnG
author_rank: Frequent Contributor
timestamp: July 31, 2017, 02:17:20 pm
content: If you haven't already bought it, you probably don't have an intrinsic love for old test equipment. If you are new to electronics, it's not where I would start.I had one of those old scopes. I found them incredible frustrating to use, since they don't have a triggered sweep. Since it was my first scope, I thought I would miss it. I never have...