Very nice VTVM. The reason for no range at the VTVM for 300VDC is IMHO that the VOM already has 20k/V x 300V = 6MOhm compared to the 11M of the VTVM. No big deal.
Have a safe and enjoyable trip Vern. Hope to see some nice videos from Thailand . I especially like watching them after coming in after shoveling a foot or two of snow :( .
Great work getting it to be a useful piece of vintage test equipment once again. The guy you bought the test probes is great when it comes to parts for and specific test probe sets for a particular unit. Happy and safe travels.
I knew those existed , but I never noticed one on the bay until now .... I only look on there when looking for something , it's not a favorite hangout of mine .... I do have a straight up 630 , not the 630 NA you have ........ Plus another that I call a parts donor , I got it for spare parts , I never tried it when I got it .... The back cover was in better shape than mine ...... I also have a mint condition RCA WV-77 E VTVM , those VTVM are great for aligning 2 way radio receivers ... Take Care Mon Ami ....
Nice job on a great instrument. Your "grumpy" comments on yourself is so hilarious... give yourself some more credit. Anyway it is a shame how some people abuse these old meters as if they're utterly worthless. To the contrary these are so well-built, real old-fashioned quality, and very useful in many situations. They're amazingly accurate as well when handled properly. Have a great time in Thailand, and send us a video after consuming a extra-nuclear Pad Thai.... I had one years ago, in a thoughtless moment, delicious, but my tortured cries were audible for miles.
I picked one of these up today for £10 from a radio rally. It's the 100w version and looks like new, complete with original tip and not been used much. Great pieces of kit when used within their limitations.👍
8:50 What do you mean? A zip file is just an archive file. You can extract it and scan with a virus scanner before executing it. A file on a thumb drive or CD isn't any safer.
I've been working in tech for almost 20 years, all of it in product hardware (and 14 years of it at three of the most familiar tech names you've ever heard of). Moisture definitely absorbs into plastic - with SMT rework, we use desiccant cabinets to store moisture sensitive components - and then before we do any rework, we do a parts bake at 125°C to drive out the moisture. Moisture can be a huge problem while soldering - if enough of it is inside the plastic when you bring the component to soldering temperature it can rupture the plastic case of a component with the increased vapor pressure. For the IF filters for future repairs, I'd recommend buying new ones, verifying the performance characteristics, then "baking" them (125°C), and storing them in a heat-sealed mylar bag with a desiccant (or several) packet to keep them dry.
Wow, I never imagined that a tarnished power plug could shut everything down like that! An important lesson, well demonstrated. Thanks for all the great content Sir! - JRH
I have to say Vern, for a so called half assed effort, it looks pretty good. I tried a new method for dial 'glass' forming which came out pretty good. It is in the next video I think. Good little tunes at the end 😅
HI David, Lots of Warts the camera didn't catch. But this was a rescue. Just wanted to save it from the bin. Love the way your dial face came out. I would never have noticed the missing number. Thanks for stopping by.
My lifetime supply of glass for vacuum forms are antique TV plate glass. For (as you say) the young wiper snappers, very old TV's had round picture tubes and the picture tube did not have a piece of tempered glass bonded to the front of them. They used a piece of flat plate glass in front of the picture tube. Anyhow, I have around 40+ pieces of that I got from my grandfather and uncles closed radio TV shop.
1:09:50 I would also suggest some guys are so quick to replace original parts with repo's. I would tend to suggest that the original, in most cases, would be of better quality and worth salvaging if possible. You showed that with the dial lamp holder. Which was no more work than popping another on. Look at what happened to your "new" number 47 lamp. I always look to trying to take apart an original component to attempt repair on things like this. A lot of the time, old stuff will come apart easy peasy. For example I have taken apart a couple late 40's house light flip switches on the blink. These things just had crimp pins (now they are riveted or worse). Cleaned out grime and worked great again. Ditto on the head light switch in a 1960 Allis D - 17 tractor. The knockoff stuff a lot of the time is not of the same caliber.
I would suggest to everyone, that a purchases an isolation (especially cut rate price stuff off the web - temu, Amazon, China) transformer, make sure you have confirmed it for actual isolation. A couple of good videos showing how some cheap stuff is made. One shows how the step down transformer isn't properly insulated between primary and secondary. The other shows a short between primary and secondary caused by manufacturing glitch. Third is about an extremely dangerous product. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-rwEh4jsVew0.htmlsi=bkHTdu0G5bHqWBSO ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-3Hdn0MuCK_0.htmlsi=B0NYdetUgdPSWQaW ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-msr4ug7tc-k.htmlsi=cb7GlV5kC54eZ7ej
So here I am again, 2 yrs after first posting and I've had to change the filters in my 897 after one turned bad, the usual large signal fluctuation and static crashes. I mentioned at the time that TWO had already been changed but an old one left in. Can you believe that!👎 I might add that the bad one had the usual green corrosion inside and it was definitely moist, almost like a paste, not dry and powdery. Anyhow I've changed all 3 and the radio lives again!👍 I wonder if giving the filters a coat of varnish or lacquer or some other protective coating would prevent or dramatically slow down the moisture absorbance problem?
All anti virus software as well as the default windows defender will unzip and scan anything you download. As long as there isn't a password on the zip file, they are no more dangerous than any other installer or executable
take that original speaker, remove the felt dust cover then turn it upside down and gently tap the magnet coil. While doing this put a low volume vacuum hose below the voice coil area to help remove debris. While this is going on, move the cone through it's travel while listening for a reduction of the noise. Don't give up on it yet, and there are several other "dodges" that can be applied too. Nice dis on the dumpster in chief at the beginning fella!
I reckon this video proves your theory of moisture ingress trashing these filters. If this is an ongoing problem with these, as it seems to be and any replacements will eventually suffer the same fate, it's a pity there isn't a suitable socket available to fit them, which you could solder onto the board and make subsequent filter changes a few minute job instead of the long, eye straining nightmare it is.
That set may not be of much historical value, I was surprised by the sound quality when you had fixed it and treated the speaker. Even over YT compression and whatnot it sounds pretty good.
That is a very strange agc circuit. Could they be taking some of the negative voltage from the grid of the local oscillator through the 15 meg resistor to power the delayed agc? And as for the loop antenna I don't have any idea what the 3rd loop is for. Seems like its just radiating the local oscillator and IF signals needlessly. I wonder what it would do if you disconnected and bypassed it? It's a definite head scratcher for sure, but it does seem to work well.
Ti act's like a gimmick CAP. Engineers wanted to screw with radio repair technicians, (and a laugh) about their deign.! They designed it just enough to make it work!
Probably not a timely suggestion any longer, but I have had some success in the past, coating fragile labels with a couple coats of water based acrylic clear coat prior to masking them. It seems to toughen the surface and reduce lift off when masking. Always enjoy your work on these old pieces, thanks! - JRH
I often just spray Clear Flat lacquer on them. The UL one that came apart (lost the black ring) was delaminating to begin with. But thanks for the tip and for watching.
