Mark's Late Night Laboratory

I got this Data Precision 1450 bench multimeter a while back on E-Bay for a few bucks, that only because I like the looks of Panaplex displays and not very many digital meters used them. It's basic, manual ranging, 4.5 digits. This was made in 1976, and used DP's "Tri-Phasic" A to D conversion... which was really nothing special.

The monstrous HP 3585A is back in business and in place on the shelf after recapping the low voltage switching power supply boards. With my age and severe arthritis I'm getting to the point I won't be able to move this piece around for much longer.

My HP 3585A spectrum analyzer is down from the shelf for repairs. Something went "pop" last night while I was using it, then it shut down and the fault alarm sounded off. This thing weighs about 85 pounds!

Gigundous Staco 3PN2210 22 amp variac. This was a freebie that was being tossed out by a sound and lighting contractor where I work as they said it was tripping the breaker on occasion. I took it home and checked it, and indeed my breaker tripped immeditately. The issue was the rubber insulated wires inside the power cord were stale. Just had to get some new cord cable at Lowes and fabricate a new cord. This is still a current model from Staco that's around $1200.00 new.

https://typewriterdatabase.com/1972-ibm-selectric-i.24313.typewriter

Here's my fully restored IBM Selectric "1" 715 shown on the Typewriter Database. Yes, there's an online database for old typewriters that's actually one of the largest databases out there for any vintage machinery. 😃 I had this stored in a box for over 30 years, untouched. I bought it as surplus when I worked at M&T Bank in Buffalo as the offices were being switched to PC's and word processors. These and darker green Selectric II's were the "standard issue" M&T Bank corporate typewriters, and they gradually scrapped hundreds of them. I had to put a new cycling clutch and clutch shaft pulley in this. It took about 12 hours of work to replace and readjust everything as this was a "first" project of this kind for me. I bought a cheap parts donor machine from Marketplace to get some of the items I needed that got broken as it bounced around throughout moves.

1972 IBM Selectric I on the Typewriter Database From the Virtual Typewriter Collection of Mark Palmer: 1972 IBM Selectric I | 1972 IBM Selectric "1" Model 715, mint green with...

My IBM Model A power roller is on it's way back from JJ Short in Rochester, NY. Maximum runout across the roller is .010, so my original recoated well. As suspected, my original rubber roller was too hard and slick from age for the cams to get a good bite to it. There's a notation on the frame of my typewriter that states "Replaced roll, 5-69." It was as old as I am.

IBM POWER ROLLER in 80 SHORE A
Runout old rubber .004
Runout Core .003
Runt out new rubber .004

I worked on the IBM model A for a while, mainly cleaning everything. Doing some research from the serial number, my typewriter was made in 1949. I got everything that was gummed up free, the motor spinning the power roller, and after much fiddling around everything looks to be working. Several small springs were missing, keeping the space bar and ribbon advance from working. I cleaned the power roller rubber, but it's well too hard to work good again. Even rubber rejuvenator didn't help it. Some keys strike good, others too soft to print decently as the cams slip too much on the roller. No new power rollers are available for these anywhere at any price today. Power rollers in these typewriters were usually replaced every 2-3 years as routine maintenance when they were in regular service. But hope is not lost. The roller has been removed from the typewriter, and is at JJ Short and Associates in Macedon, NY (www.jjshort.com) at present. They have recovered dozens of these IBM power rollers with new rubber, along with recovering typewriter platen rollers. So I should have a newly recovered power roller soon. https://www.jjshort.com/Power-Rollers-Return-to-their-Roots.php

This old clunker has been following me through moves for 3 decades, boxed up with a bunch of other items I bought at the Walden Ave. flea market in Buffalo in the early 1990's. In 2021 I restored a Fisher 400 stereo receiver I got from that flea market which turned out nice. I could get a few $$ in scrap metal for this, but it's so damn sinister and industrial that I have decided to fix it up this winter. It's an IBM Model "A" electric office typewriter. I also have an old IBM Selectric in another box I bought as surplus from M&T Bank in Buffalo when I worked there.

The cool stuff 😎 Top view inside of HP 3580A 50 kHz spectrum analyzer

A: Business end in card cage with cover removed = Mixer/IF/Filtering boards. Low voltage power supply regulator board is below this in picture, heat sink screws to top cover.
B: Digital frequency tuning
C: Display vertical and horizontal adjustment board (HP moved this inside from previously having the adjustments on back panel.)
D: Analog to digital conversion and 8 kB of digital storage memory. CRT is directly underneath this board. For what was a $5000.00+ SA they could have used the 1740A CRT with the awesome flood gun backlight rather than no backlight at all, but I guess they wanted to keep it more compact.
E: CRT high voltage power supply
F: CRT display driver

Input level preamp and atteunator board on underside of 3580A, along with the rechargeable battery pack option. This had been emptied of its batteries and disconnected. LV power transformer and filter capacitors are tucked away on lower right of back panel.

1 kHz deviation on a 12.5 kHz signal here with the HP 3580A, and things are looking pretty good with a few minor touch-ups outlined in the service manual. The same signal is displayed in second photo through my 3585A that has a little more dynamic range, was helpful for making comparisons. Will be looking at close-in signals soon with the low RBW filters down to 1 Hz.