Yes, the new rubber hammers are available from David Tumey. I think he wants about $7 for 10 of them. I have a supply of them here in the UK for anyone that needs any.
Regards Rob > -----Original Message----- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Cory > Heisterkamp > Sent: 31 May 2015 15:48 > To: General Discussion: On-Topic Posts > Subject: Re: PDP-12 Restoration at the RICM > > Michael, > > Sounds like you're making some real progress. Next time you're near the > ASR33, check the rubber hammer for the print cylinder. These have a tendency > to self destruct and in doing so, destroy the cylinder itself...and they can go at > anytime. There's a fellow on the Greenkeys that has tooled up and is producing > replacements; same profile as the original and easy to install. Cheap insurance, > really. -C > > > On May 31, 2015, at 8:08 AM, Michael Thompson wrote: > > > We spent some time on the console Teletype that came with the PDP-12. > > The platen was nearly impossible to move, so the Line Feed did not > > work. We removed the platen, and found that the plastic in the bearing > > area had swollen and was binding. We sanded, cleaned, and lubricate > > the bearing surface and the platen now turns freely. On reassembly we > > found that none of the Control Characters like Line Feed or Bell would > > work in Local Mode. We fiddled for quite a while, but did not find a > > problem. We speculated that something got bent when it could not move the > binding platen. > > > > We found a bad SN7474 E13 on the M706 Teletype Receiver flip-chip from > > the PDP-12. We will repair and test it next week. > > > > We borrowed the M706 Teletype receiver from the PDP-8/I and connected > > the Teletype to the PDP-12. We loaded and ran a toggle-in program that > > echos the keyboard to the printer. We were a little surprised when > > everything in the Teletype worked OK. We were even more surprised when > > the Teletype now worked correctly in local mode. > > > > We borrowed the console cable from the PDP-8/I and connected my laptop > > to the PDP-12. The terminal emulator worked correctly and echoed > > characters to the PDP-12 and back. > > > > We toggled in the RIM loader and then loaded the LBAA BIN loader from > > my laptop. We ran the BIN loader and loaded and ran the PDP-8/I > > Instruction Test #1. It actually works OK! > > > > We tried twice to load MAINDEC-8I-D02B-D Instruction Test #2, but > > failed both times. Running that diagnostic and others will be the > > project for next week. > > > > Al Kossow posted LOTS of PDP-12 manuals to Bitsavers. One manual > > includes the allowable ripple for the power supplies. They allow > > 3,000mV of ripple on the -30V supply for the core memory, so I guess > > that the 180mV that we measured two weeks ago is OK. > > > > On Mon, May 25, 2015 at 8:07 PM, Michael Thompson < > > michael.99.thomp...@gmail.com> wrote: > > > >> Today we pulled all of the M113 flip-chips and tested them because > >> SN7474 and SN7400 ICs seem to be a problem in these early DEC > >> systems. The ones in slots J33 and K30 were bad. Replacing them fixed > >> the problem with the JMP instruction. We did some more testing with > >> the toggle-in programs and found that ISZ cleared the AC. Replacing > >> the M119 in slot H28 fixed that. All of the toggle-in tests pass, so the > processor is substantially functional. > >> > >> Core memory in field 1 with addresses X5XX didn't work. We replaced > >> the > >> G221 in slot D10 to fix that. > >> > >> We tried the ASR33 Teletype that came with the system. The mechanics > >> were sticky from not being used for 30 years, but we got most of it > >> free and working. We could send characters to the Teletype, but could > >> not receive anything. The M706 receiver failed in the board tester. > >> The spare is also broken, so we need to fix both. > >> > > > > > > > > -- > > Michael Thompson
