test-drb March 2006

test-drb@ccmp.vtda.org

233 participants
501 discussions

by drb＠msu.edu

> I've not found the number yet, but are you interested in getting > rid of them? I've got a bunch of HP hardware and could likely use > them. Some other HP cables: > > http://rikers.org/gallery/hardware/20050417_214520 > > The centronics connectors are 50 pin card edge on the other end? or > higher pin count? Same pin count, but it's centronics-to-mrac or winchester-to-mrac. Here's a pair of images showing the two types: http://yagi.h-net.msu.edu/img_1848.gif http://yagi.h-net.msu.edu/img_1849.gif The camera did funny things to the colors; the jacket of the cables have a silvery color, and the connector shells are metal. They're cleaner than they look. They're probably available. De

18 years, 3 months

OT laser printer question

by Watzman＠neo.rr.com

Re: ********** > If its the physical letters on the paper, if they are lumpy or if they > are smearing if touched then your High Voltage power supply board is > starting to fail. Intuitively, if the toner smears when touched, I'd assume it wasn't being fused properly, and would investigate the fuser and its control system first. ********** That is correct. If the toner smears when touched, the problem is in the fuser, and it has nothing to do with the HV power supply, drum or anything else. In early laser printer (up to at least the Canon EX engine in the Laserjet 4 and, I think, 5), fusing was done with heated rollers. The upper fusing roller was an aluminum roller with a silicone (non-stick) coating, and inside the hollow roller was a high-power tubular halogen lamp (500 to 900 watts). The lamp was line-operated, thus different for 110v and 220v printers, and the cause of failure was almost always that the lamp had simply burned out (although lamp control problems are possible, but not common -- the lamp does not burn continuously, it's cycled based on the roller temperature). The lamp can be replaced ($30-ish, typically) by a technician who knows what they are doing, but it's more common to replace the entire fuser assembly ($100+ in most cases). Later models (those that have near-zero warm-up) use "thin film fusing", which is more sophisticated, much more power efficient, and also more complex and difficult to repair unless you go for the swap of the entire fusing sub-assembly.

18 years, 3 months

cctalk Digest, Vol 31, Issue 21

by dm561＠torfree.net

No problem if you can find a copy of PCAnywhere/Carbon Copy/Freeware equivalent; Serial or parallel port connection would be trivial, NetBIOS no problem either; don't know about TCP/IP. mike -------Original Message Date: Fri, 10 Mar 2006 17:10:06 +0000 From: Jules Richardson <julesrichardsonuk at yahoo.co.uk> Subject: Re: C Compilers for (MS)DOS Ta, will take a look! Ultimately I'd like something that sat on the network and could be controlled remotely (and be able to say FTP or HTTP or NFS or SMB transfer data to a remote box holding disk images) - but that's a colossal amount of work to get going under DOS! Serial port control is a little easier though, and at least means the machine with the drives in doesn't need its own keyboard / display. Or I could just get a KVM, but that's no fun :-)

18 years, 3 months

HP 9915B Repair Help Request

by jsievers＠nadhh.Get-on-IT.com

Hi Tony Duell. Could you remember this thread below ? I have the same system and need some help to reassemble an HP tape drive. After disassembling and ultrasonic cleaning of a HP-Tape-Drive for this HP9915B two parts remaining unassembled. Two parts, small thin chromium-plated metal stripes, are droped down out of the device during dismantling. I could not find out where these have to be mounted again. Here you could see few pictures of these parts. http://www.nadhh.hanse.de/CMuseum/HP/HPTapeHilfe.htm I would be really happily if someone could help me to get out where these parts has to be placed back into that tape-drive. Could you help me ? With regrads j?rgen > > Hi, > > I have a faulty HP 9915B (the industrial version of the HP 85B). I don't I guess I should respond :-). I don't know anything about the 9915B, but I have a reverse-engineered schematic of the 9915A, and from what yuo say below the PSUs are very similar. (Incidentally, the 9915A schematic is on the HPCC scheamtics CD-ROM, should you want it) > have the right circuit diagram for it, only the ones for the HP 85A and 85B > from their service manual. Looking at the 9915B it seems to have a similar > circuit, but some of the differences I can't understand. > > So far I have checked the following: > > rectifier output = 32V DC (OK) > but none of the regulated voltages are working (eg the +12V line is at > +1.4V, similarly +5V, -12V are around 1V). Ouch! I am going to assume it _is_ the same PSU as the 9915A. From what you say there, it's clear that the crowbar (Q4) hasn't fired, since this shorts the 32V (Vin, on my diagram) line to ground. > > The power supply is based on DC-DC converters running at around 30kHz. I > found the PWM regulator (U30, equivalent to U1 in te 85B), and this is > generating pulses on pin 3 and has a 5V reference on pin 16. This part is > labelled SG9496, the 85 uses a SG3524 (datasheet on the web), the pin-out > seems to be the same. My diagram shows U30 as an SG3524, but that may be because it had a custom HP number on it, and I found it was pinout- and functionally- identical to the 3524... > > Signals on the other pins are:. > . > pin1 - OV DC (would be around 3V if ok) Should be a potted-down version of the 12V line, If that's missing, then pin 1 will be olow. > pin2 - 3V (ok, derived from %V) Potted sown from the Vref ouput (pin 16 > pin 9 = 0.5V (see below) This is called 'comp' on the 3524 datasheet. It's the output of the error amplifier and what's worth knowing at this point is that it can be pulled low exernally to shut the outputs down. > pin 7 = 0.2V to 4.5V ramp as per 85 service manual OK, so the oscillator is running (that's the timing capacitor pin). And the reference output is also present. U30 may well be good. > pins 12 & 13 = 32V DC Outputs to the chopper (collectors of the output transistors, the emitters (pins 11 and 14) are grounded). It's clear the chopper is not being driven. > > I traced pin 9, and this is connected to C20 which in turn is connected R23 That's the first compoent reference difference (or I've made a mistake). On my diagram, C20 is the dcoupling cap on the V+ (pin 15) supply input to U30. There is a compenstation network, 0.1uF in series with 8.25k between pin 0 and pin 1, though. > then pin 1 (similar to 85). pin 9 is also connected to diode CR4 which goes > into transistor Q2 (which in turn is connected to 0V). It looks like pin 9 > is being pulled down by CR4 and Q2 as these are both forward biassed. One > question is what does CR4 and Q2 do? Are they part of some protection > circuit? Ah.... Q2 is the overcurrent protection transsitor. It's turned on by U31 (LM311 comparator), which is driven from T1 (9100-0456 transformer) which measures the current through the chopper. If that current is too high, then U31 triggers, turns on Q2, and shuts the supply down. Whatever you do, don't disable this circuit. If there is a short, the results will be spectacular and expensive. > > The output on pins 12 &13 has no negative going pulses, so the psu never > gets started up. pim 12 connects to an 820 ohm resistor (number hidden) > which then goes to transistor Q5 (the main switching transistor, Q1 on the > 85). This is different to the 85 which uses an intermediate driving Watch out!. Q5 is not a simple transsitor (at least not in the 9915A). It's a PIC645, which seems to be some kind of darlington with the flyback diode, etc, in the package. It's roughly a PNP transistor, emitter to Vin via T1 primary (current sense), collector to pin 3 of T2 (12V supply transformer primary tap), base to the output of U30 via that 820R resistor. > tranhsistor. I guess this means the U30 PWM has to drive more current. No, Q5 is more than one transsitor. OK, what I'd do next is look at U31 (assumeing it's a 311 comaparator). The -ve input should be at about 2V (potted down from Vref again), the _ve input should be 0 (it comes from the sense transformer, but with no AC current flowing through the chopper, it can't be doing much). Then see if Q2 really is turned on, or shorted, or what. > > Any advice gladly received, eg source or equivalent for a SG9496 controller, > copy o9f service manual would be great too! Hope that helps -tony

18 years, 3 months

11/34a problems continue

by henk.gooijen＠oce.com

If something "blew", there must be a major 'problem' somewhere else! Did you find out why the board "blew"? Tip on power supplies (in the 11/34): check the rectifier bridge. Often (for what's "often" worth) a diode inside is open circuit, thus the full-wave sine is used just for one half. I agree with Tony. You must do several simple voltage measurements at the power supply, distribution panel, connectors, sockets, etc. Basically everything a connection "meets" from the PSU to the backplane. Don't forget the wire itself! - Henk. > What do you mean 'the board blew'? Did the magic smoke come > out (if so, out of what?). Was there a hole burnt through the > board, melted traces? > > FWIW, unless the board was actually burnt, I think it would > be repairable. I once did something very silly to a H754 > brick with the result that 4 transsitors blew apart, one > ressitor totally burnt up, etc. > And that brick is working again now. > > And the +15V board is actually very simple. It's a linear regulator... > > > deal with and it came back to life - sans the H745 coming up. > > > > I will ask you once more. Have you done any actual electrical > tests on this PSU? > > -tony This message and attachment(s) are intended solely for the use of the addressee and may contain information that is privileged, confidential or otherwise exempt from disclosure under applicable law. If you are not the intended recipient or agent thereof responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution, or copying of this communication is strictly prohibited. If you have received this communication in error, please notify the sender immediately by telephone and with a "reply" message. Thank you for your cooperation.

18 years, 3 months

Brief mention of S-100 bus in EDN

by cclist＠sydex.com

Tiny feature article in EDN online about S-100 bus: http://tinyurl.com/eclyo

18 years, 3 months

Telling (MS)DOS about a second floppy drive...

by julesrichardsonuk＠yahoo.co.uk

Can't remember if there's a way of doing this or not! I've acquired a nice compact HP PC which I had plans to use as a data recovery box - except that I've just discovered that the braindead BIOS only supports one floppy disk drive; I need a 3.5" HD drive as the first disk and a 5.25" HD drive as the second... Assuming that the FDC will work with two (I've never heard of an FDC that won't?), is there a way of telling MSDOS about the second drive even when the BIOS refuses to acknowledge its presence? If not, the whole machine's off to the tip... stoopid PCs, grrr! (actually, I'll freecycle it, which is where I got it from, but the thought of it being crushed makes me feel better right now) cheers Jules

18 years, 3 months

C Compilers for (MS)DOS

by julesrichardsonuk＠yahoo.co.uk

What's the state of play regarding DOS C compilers? I might have a need to do some DOS-based C development work - are there any good-but-free DOS compilers about? I did have Turbo C on tape, but I haven't tried to read those tapes in years and wouldn't hold out much hope of them still being intact... ta Jules

18 years, 3 months

IBM System 34 available

by sellam＠vintagetech.com

See below. Contact: Laura.Childers at sandersbros.com I think it's in Georgia (the US state, not the country). -- Sellam Ismail Vintage Computer Festival ------------------------------------------------------------------------------ International Man of Intrigue and Danger http://www.vintage.org [ Old computing resources for business || Buy/Sell/Trade Vintage Computers ] [ and academia at www.VintageTech.com || at http://marketplace.vintage.org ] ---------- Forwarded message ---------- Date: Fri, 10 Mar 2006 11:26:12 -0500 From: "Childers, Laura" <Laura.Childers at sandersbros.com> To: donate at vintage.org Subject: IBM system 34 Morning, Would you be interested in an IBM system 34 and printer? Thanks for your time - Laura Laura A Childers Sanders Bros., Inc. Phone 864-487-6118 Fax 864-487-6170 Laura.Childers at sandersbros.com

18 years, 3 months

another printer question

by rtellason＠blazenet.net

Got an IBM 4019 here, and it has a postscript board in it, I'm told. I can't seem to find any info on that option. The problem is, every time you power the thing up it kicks out a page with stats and settings and whatnot on it -- which over time is a hell of a waste of paper, particularly if you're not printing much. Anybody know of a way to make it stop doing that? -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, a critter that can be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin

18 years, 3 months

← Newer
1
...
34
35
36
37
38
39
40
...
51
Older →

Jump to page:

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

test-drb March 2006