My last email to him was in Sept last year asking if he received the 7CT1N service manual I sent him, never got a reply. Chuck

I'm interested in the scope. It's one of the few models I don't have yet. If you are near Indy I can have it picked up by a friend. Chuck

I am working on a 1L10 SA module and was wondering if anyone has any experience on these. The only manual I can find is from the TEK Wiki site, it is good with schematics and theory but very little on

I tapped a razor blade between the two halves at the glue joint and it came apart easily. Maybe it was just a fluke, will know when I try another one. Chuck

A couple years ago I bought an HP 8753B Network Analyzer with test set that was cheap (under $400) as it was listed not working, bad CRT. I took a chance on it. Got it home and just had to clean the b

Steve, I have learned that lesson the hard way also, find it, buy it and take it now. The scope price was too good to pass ($30) and I have had the manual for the 230 for years and thought it would be

I recently picked up an R568 with 3S6 and 3T6 plugins. I'd like to find a Model 230 Digital Unit for it. Would prefer a rack mount unit but not going to be particular. Anyone have one for sale or trad

If you're interested in the practical use of this mechanical amplifier look at patents 712930, 783750, 796743, 876350 The last two are for actual production phonographs produced between 1905 & 1908. C

Go to USPTO site: https://patft.uspto.gov/netahtml/PTO/srchnum.htm Enter patent number in Query box then Search, then Images Most early patents are only available as images. Chuck

The RCA 1" CRT is a 913. RCA used in their 1936 Model 151 scope, National used it in their Model CRM, Clough-Brengle 1935 Model 105, and a number of homebrew scopes in the mid 30's. Pictures: http://w

Around the turn of the 19th century Daniel Higham invented a mechanical amplifier for use on early acoustic cylinder phonographs. The original patent is #678566, it's easier to read the patent than tr

Martin, I read your posts about using the Metrix with a 576, got me thinking about trying the same thing with my New London 901A Transconductance Analyzer. Seems to be similar to your Metrix, all conn

I bought a couple of Dennis's VTCT boards when he first produced them. I built a couple of crude adapters to use on my 576 which worked pretty well but were cumbersome to use. I didn't like the use of

Does anyone have a readout board (670-0635-01) for a 7504 scope they would be interested in selling or ? Contact me off list. Chuck -- See Early TV at: www.myvintagetv.com

Chris, Sorry no, I am using both of them. One is dedicated as a tube CT, the other for semiconductors. Chuck

The CR70 has 2 functions REJUVENATE and RESTORE. From the manual: In REJUV function, cathode and G2 are tied together. Normal filament voltage is applied and a 1K ohm resistor is in series with discha

I've had good luck using a Sencore CR-70 restoring a TDS-648A and a HP3562A CRT, both were so dim as not usable. Running the filament about 40%-50% higher for a time was a old method to sometimes make

Andy Removing the HV board is a PIA as you have to unsolder 11 or so connections on the top of the board and a screw holding the heat sink for the oscillator transistor before you can work it out. Get

Jeff Most of the scopes I've picked up have been in storage for many years and lots of dust. I usually just do cleaning with a compressor for dust and loose dirt and lots of elbow grease for stubborn

I've been reading this thread and am wondering what 500 scope are you moving and how far? I've moved many of them in the back of my truck just wrapped in a moving blanket and secured so they can't sli