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101090 discussions

Mac SE/30 making zipping and buzzing noises

by marc.verdiell＠gmail.com

A classic case of Mac SE leaking electrolytic caps. Soon your sound will disappear completely. Then your Mac SE/30 won't even boot. You can confirm looking for shiny leaks traces around the caps. Very easy to take care of. Replace all of them, as they will all go bad. But there aren't many of them, I think I counted just 11. Most of them are of the 10 uF variety if I remember. Surface mount with leads hidden underneath the caps, a bit annoying to remove, but you can pretty much break them off the board carefully. The leads should break off at the cap and stay attached on the board. Then desolder the lead remnants and clean off the old solder with copper wick until you get pristine pads. Clean any spilled electrolyte under the caps thoroughly. Replace them with regular 10 uF ones - or whatever value is needed. I used standard axial through holes ones, just soldered the bent leads on the traces. It's even written on the board where the + go! Thanks Steve Jobs. If I could attach pictures of the before and after, I would... I can send them to you off line if you want. Actually I see your email, I will. Marc On 20/03/2015 6:39 PM, <dave at 661.org> wrote: > I'm gradually restoring a Mac SE/30. Today I got a new PRAM battery > and installed it. There was no battery leakage, so I'm good there. > The machine seems to run just fine. The big problem now is that even > though nothing should be emitted from the speaker, I'm getting zips, > buzzes, and burbles from it depending on what the computer is doing at > the time. I'm quite sure the the sound circuitry is somehow picking > up RF noise from the system bus. What does this symptom indicate? > Should I recap the whole machine? > > David Griffith > dave at 661.org

11 years, 4 months

A challenge from the Spectrum BASIC manual is finally achieved

by lproven＠gmail.com

30 years after it was set by Dr Stephen Vickers. An orchestra of a dozen -- networked! -- original ZX Spectrum computers plays Mahler's 1st symphony. A rather lovely 10min film: https://www.youtube.com/watch?v=LxPXLIALJJI -- Liam Proven ? Profile: http://lproven.livejournal.com/profile Email: lproven at cix.co.uk ? GMail/G+/Twitter/Flickr/Facebook: lproven MSN: lproven at hotmail.com ? Skype/AIM/Yahoo/LinkedIn: liamproven Cell/Mobiles: +44 7939-087884 (UK) ? +420 702 829 053 (?R)

11 years, 4 months

IBM 5100 Restoration in progress

by santo.nucifora＠gmail.com

Hi All, Long time reader, first time poster. I am in need of some assistance in trying to revive an IBM 5100. It is a Basic 32k version that was in rough shape. You can see pics here: http://vintagecomputer.ca/ibm-5100-before/ I've been able to clean it up but when I fire it up I see a single "A" on screen. I can't seem to get into any diagnostic modes. The single "A" indicates an issue with the F2 Base I/O card. Some of the ICs do have some rust on them but I'm wondering if it might be the "bridge connectors" between the Base I/O and Controller (CPU) card. Are they directional or can then be swapped or turned around? I may have not kept them in the correct orientation but I don't see any mention in the Maintenance manual. I, pretty much, need someone who has one to take a picture of the top of their Base I/O and Controller cards. Any help is much appreciated. If someone happens to know a common issue that would make the "Bring up Program" stop at A, I'd love to hear about it. Thanks in advance, Santo

11 years, 4 months

Tek 1200 series GPIB interface available

by jnc＠mercury.lcs.mit.edu

Hi, I acquited (with a Tek 1240 I recently got) a 1200C02 GPIB Comm Pack, which I have no use for. Dunno if it works or not. Looking for a good home for it - shipping plus whatever donation the receiver feels is appropriate. Noel

11 years, 4 months

Looking for PSS RAM65 S100 Manual

by philip＠neoncluster.com

Hi all, I have a Problem Solver Systems (PSS) RAM65 card that I would like to get working in my IMSAI 8080, but I can not find any manuals for it online. Does anyone on the list have a manual they could possibly scan for me. Much thanks in advance. Philip

11 years, 4 months

DEC PDP-11: 330 XXDP listings scanned from micro fiches

by shadoooo＠gmail.com

Wonderful!!! :) Andrea

11 years, 4 months

DEC PDP-11: 330 XXDP listings scanned from micro fiches

by jnc＠mercury.lcs.mit.edu

> From: J?rg Hoppe > Over the last months I scanned micro fiches with XXDP diagnostic > program listings ... I digitized 330 listings from 452 fiches, with a > total of 53545 document pages. Wow! That is a fantastic job, and I'm sure they will be incredibly useful to the community. Thank you! Thank you! Thank you! Noel

11 years, 4 months

DEC PDP-11: 330 XXDP listings scanned from micro fiches

by lbickley＠bickleywest.com

Joerg, On Sat, 21 Mar 2015 07:46:09 +0100 J?rg Hoppe <j_hoppe at t-online.de> wrote: > Hi all, > > Over the last months I scanned micro fiches with XXDP diagnostic > program listings. > These listings are essential for repairing PDP-11's (or enhancing > SimH). I digitized 330 listings from 452 fiches, with a total of > 53545 document pages. > Almost all of them should be new stuff. --snip-- Great job. A serious "labor of love". Thanks a LOT! Cheers, Lyle -- Bickley Consulting West Inc. http://bickleywest.com "Black holes are where God is dividing by zero"

11 years, 4 months

Kaypro 4 + 88 boot disk (81-232 ROM)

by brain＠jbrain.com

There seems to be quite a few options for a boot disk for a K4+88 here: http://www.retroarchive.org/maslin/disks/kpro/ The unit has a 81-232 ROM. Gene (again, thanks), sent some disks, but the 81-232 one did not work. I created a disk from one of the images on the site, and the unit boots (yay!), but not sure if I am using the best image for the unit. Any particular image I should use? Also, any links to the '88 stuff for this unit? Jim -- Jim Brain brain at jbrain.com www.jbrain.com

11 years, 4 months

How to save two Mitsubishi M2896 drive (spindle motor smoked!)

by enrico.lazzerini＠email.it

Well, i desolder the LB1620... it has obvious signs of burning under the chips and also on the pcb. I saw the smoke coming from that place but I thought it came from one of cap of 2700pf instead came from the chip. The short circuit between +24vdc and the ground is gone out.   +24vdc go just at pin 4 of the LB1620. +24vdc to R112 and the D102 Zener that is saved so from here to pins: 19, 2 and 12 of the LB1620 then it continue to pin 16 of the TC9142P. The datasheet of this last one say that the power voltage would be between 5Vdc and 9,5Vdc. So would this say that the zenere has to be from 5 to 9 vdc? Have i to measure the exact voltage on pin 16 of the TC9142P without the  LB1620 and how have i to expect?   The LB1620 is smoked. What other components must be tested to ensure that the new LB1620 can not be broken just fitted?   Thanks a lot.   E.     --------- Original Message -------- Da: "General Discussion: On-Topic Posts" <cctech at classiccmp.org> To: "General Discussion: On-Topic Posts" <cctech at classiccmp.org> Oggetto: Re: How to save two Mitsubishi M2896 drive (spindle motor smoked!) Data: 02/03/15 04:20 Indeed, pin 4 (Vcc1) should be +24V, this is for the motor windings drive. You need to look at pin 19 (Vcc2) of the LB1620 or the voltage across zener D102. Follow the pcb trace from the junction of R112 and D102, goes to pin 19, looks like pins 9 & 2 as well, and on to supply the other ICs. On 2015-Mar-01, at 1:38 PM, Enrico Lazzerini wrote: > > Mhmhm... i checked the pcb. The LB1620 pin 4 is wired to the pin on which I > think comes +24vdc... so... let me check what could happens before. Could > happens that is it broken something and it goes to this little pcb +24vdc > instead of 12-15vdc??? > > I misured the voltage coming to this pcb and over there is +24VDC > This explain well the why this pcb smoke and it is hot. > > > Enrico > > -----Messaggio originale----- > Da: cctech [mailto:cctech-bounces at classiccmp.org] Per conto di Brent Hilpert > Inviato: domenica 1 marzo 2015 22:08 > A: General Discussion: On-Topic Posts > Oggetto: Re: How to save two Mitsubishi M2896 drive (spindle motor smoked!) > > > On 2015-Mar-01, at 9:56 AM, Enrico Lazzerini wrote: > >> Thanks Tony for your suggestions. What I means is: >> >> It happen in two distinct times every time when I used the drive to read >> through a PC with the software IMD to create images of floppy disks 8 ". > Not >> having the correct power connectors i power the drives in this way: + 5vdc >> and ground coming by a PC power supply and +24vdc and ground from a > Chinese >> power supply. I must have certainly reversed this last one even for a few >> seconds exchange +24vdc with the ground. Now both spindle motor supplied >> also with only +24vdc start smoking in the vicinity of the chip LB1620 and >> cause of cooling you can not touch it as hot it is. If I try to measure > the >> resistance between pins +24vdc and ground of each spindle motor drive i > get >> 1327ohm on FD0 while i measure 19ohm on the spindle motor drive FD1. There >> are no visible damage nor to the components nor the PCB wires. >> In both pcbs anyway the chips LB1620 sunburnt from not being able to keep > a >> finger on it. >> I searched on ebay and the only place that has LB1620 seems to be: >> > http://www.ebay.it/itm/LB1620-INTEGRATED-CIRCUIT-IC-BOX-74-/390955452872?pt= >> LH_DefaultDomain_0&hash=item5b06c2c9c8 >> >> The input's pins of the pcb are : +24vdc, ground, and the rest could be a >> control. >> >> The point is that I have no experience on these components. >> Replace the chip could make it burn again for my inexperience. >> > > I notice in one of the photos you have written 15V for the zener D102, and > on both boards they look like they have been replaced. > > D102 and R112 are a simple regulator to reduce the +24V down for the chip > supplies (looking at the photos to trace the circuit). > +24 is otherwise used directly only for the motor windings, in part via Vcc1 > on the LB1620. > > The LB1620 datasheet specifies the Vcc2 range for the 1620 to be only 8.5 to > 14V, not 15V. > > Check the Vcc2/zener level to see whether the zeners are good and what > voltage they are. > I expect Vcc2 (and the zener V) is supposed to be 12V or 9V. > -- ZE-Light e ZE-Pro: servizi zimbra per caselle con dominio email.it, per tutti i dettagli Clicca qui http://posta.email.it/caselle-di-posta-z-email-it/?utm_campaign=email_Zimbr… Sponsor: Idee regalo classiche o alternative? Trova l'offerta migliore in un click Clicca qui: http://adv.email.it/cgi-bin/foclick.cgi?mid=13327&d=2-3

11 years, 4 months

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