Re: S/23 machine update card
On 08/18/2019 06:38 PM, Dennis Boone via cctalk wrote: Folks, I've determined that the piece of my S/23 that's causing the power supply to blow its 12V fuse is the machine update card. The manual says this provides additional R/W storage for microprogram updates. That sounds like something that wouldn't be necessary for normal operation. Not knowing anything about this system, but you might check the card for a bad Tantalum capacitor. Jon
S/23 machine update card
Folks, I've determined that the piece of my S/23 that's causing the power supply to blow its 12V fuse is the machine update card. The manual says this provides additional R/W storage for microprogram updates. That sounds like something that wouldn't be necessary for normal operation. Questions: 1. Can anyone confirm that I'm not losing anything by just pulling this? 2. Anyone have a cross ref for the IBM house numbers on these chips? 3. Anyone have a spare card they'd part with? 4. As long as I'm dreaming, anyone have a set of BRADS floppies or images? Machine update card photo: https://sysovl.info/pages/galleries/ibm/s23guts/s23guts13.jpg Interestingly, the underlying PCB for this seems exactly the same as the one for the word processing feature card. Many thanks, De
Re: multi-section cap for Tek 4006
There are the old radio guys who seem to hoard NOS caps. You may want to check these guys to see if they have something that might fit: https://www.vivatubes.com/ https://www.justradios.com/ Personally, rather than depend on the condition of a very old electrolytic, I'd probably rebuild "in the can" with modern stuff. Unless you're taking about paper-in-oil caps, I wouldn't be very sanguine about really old stock--they have a tendency to dry out even in storage. --Chuck
Re: multi-section cap for Tek 4006
> On Aug 18, 2019, at 1:52 PM, Al Kossow via cctalk > wrote: >> Rebuilding cans is a common practice now, since they are LONG out of >> production. > https://www.nmr.mgh.harvard.edu/~reese/electrolytics/ Thanks, Al. This is definitely plan B, unless somebody here comes through with a miracle "oh I have those...", or "there's a pile over at X...", or "they're also used in Y so look for one of those." (Don't know until you ask, especially around this crowd :-)) cheers, --FritzM.
Re: multi-section cap for Tek 4006
On 8/18/19 1:51 PM, Al Kossow via cctalk wrote: > Rebuilding cans is a common practice now, since they are LONG out of > production. https://www.nmr.mgh.harvard.edu/~reese/electrolytics/
Re: multi-section cap for Tek 4006
On 8/18/19 1:17 PM, Fritz Mueller via cctalk wrote: > Any part-sourcing gurus out there able to steer me in a good direction here? Rebuilding cans is a common practice now, since they are LONG out of production. It is just tedious to do. There are a few people who make them, for example https://hayseedhamfest.com/products/
multi-section cap for Tek 4006
I'm working my way through a Tektronix 4006 terminal purchased of eBay right now. First stage is the low voltage power supplies, and I noticed right away that one of the multi-stage electrolytic filter caps there was running quite hot (this was with downstream electronics isolated, and a 40 ohm dummy load on the +20V supply per recommendation in the service manual.) The cap in question is a multi-section Mallory can, 150@400 / 150@250, used to filter the +185 and +320 unregulated supplies. It is C395 A/B on the schematics, Tek part 290-0549-00, Mallory part 68D20193. This terminal is so beautifully engineered inside that it would be a real shame to replace this with some sort of ugly bodge. Any part-sourcing gurus out there able to steer me in a good direction here? I have found the part listed in the various online NSN aerospace cross-referencing sites, but haven't bothered to ask for a quote from any -- I'm guessing cynically that "RFQ" + "Aero..." = 5 zillion dollars for one piece... :-) Has anybody here used one of these sites successfully? cheers, --FritzM.
Re: I need a keypunch (briefly)
> On August 18, 2019 at 12:03 PM Chip Davis via cctalk > wrote: > > > The 029 I used is in the private collection of a mainframe service > company, Will. They are not open to the public and I know of no > computer museum in the area. > I was afraid of that. Not surprising; Chattanooga isn't known as a great tech hub. That's one reason I'm no longer there. > However, if you ever get up to the Baltimore area, there is a very > extensive computer museum https://museum.syssrc.com that is curated by > another member of this list. It even includes a working Linotype > typesetter; the dripping hot lead did a number on the lobby carpet. > (OK, it did a couple of letters on it too.) ;-) > > -Chip- > Thanks for the info. I would love to go see that lead number -- and letters -- on the carpet :-) Thanks, Will
Re: I need a keypunch (briefly)
The 029 I used is in the private collection of a mainframe service company, Will. They are not open to the public and I know of no computer museum in the area. However, if you ever get up to the Baltimore area, there is a very extensive computer museum https://museum.syssrc.com that is curated by another member of this list. It even includes a working Linotype typesetter; the dripping hot lead did a number on the lobby carpet. (OK, it did a couple of letters on it too.) ;-) -Chip- On 8/18/2019 1:55 AM, wrco...@wrcooke.net wrote: On August 17, 2019 at 11:41 PM Chip Davis via cctalk wrote: Thanks, one and all, for the pointers to working keypunches. Ultimately, the closest one was in Chattanooga and I now have everything I need to fabricate the award. -Chip- Hi Chip, I'm wondering if you could tell us where in Chattanooga you found one? I'm originally from that area and go there a couple times a year to see family. If there is a museum or other public place with old computers I would like to visit sometime. Thanks, Will
