test-drb May 2011

test-drb@ccmp.vtda.org

162 participants
224 discussions

Subject: Re: Desoldering a chopper transistor

by kandres＠epssecurity.com

Desoldering a component is a learned skill. I have been in component level repair since the early to mid 1960's. I was trained for depot repair level by the USN. On normal track devices, DIPs, transistors, diodes, etc I rarely go above 650*. If the component has a large back plane of tracking on either side of the board, I will dial up to 750*. As Phil mentioned, a first attack to remove what oxidation and junk is present, is appropriate. Then I will apply some new solder, and watch closely for the "drop" of the new solder which means it has heated thru the hole to the far side. Both the internal plating of the through hole and the pin help convey the heat. Very inexpensive boards with no thru plating will be your enemy. I would not expect to find that in a PDP. An immediate application of a good vacuum to remove the solder is then warranted. If your vacuum device will not pull a vacuum against the area of skin on the outside of your hand between your thumb and forefinger, get another, it is NOT good enough. Follow that with a dental probe to manipulate the desoldered pin if possible, examining both sides of the board. You may hear or feel a "click" as the last solder whisker lets go. I have never used "braid", I have never liked it, you must heat both the braid and the track/pin to melt temperature, difficult at best. A product called, I believe "Solda-Quik", used in surface mount work, can be used as a catalyst to lower the melt temperature of some solders to around 350* and aid in the more rapid removal of the existing solder. I have done surface mount repair with this product. A lifted track can be repaired with some 30 gauge wire wrap wire stripped clean, bridging gaps, or thru holes to solid track on both sides. I have also socketed any DIP I have ever removed, if at all possible, with a good 2 side wipe socket suck as AMP. Kevin Andres Senior Technician Engineered Protection Systems Inc Nicet # 90660 Fire Alarm Systems Level II 616 459 0281 kandres at epssecurity.com epssecurity.com -----Original Message----- From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org] On Behalf Of cctech-request at classiccmp.org Sent: Saturday, May 07, 2011 1:00 PM To: cctech at classiccmp.org Subject: cctech Digest, Vol 93, Issue 8 Send cctech mailing list submissions to cctech at classiccmp.org To subscribe or unsubscribe via the World Wide Web, visit http://www.classiccmp.org/mailman/listinfo/cctech or, via email, send a message with subject or body 'help' to cctech-request at classiccmp.org You can reach the person managing the list at cctech-owner at classiccmp.org When replying, please edit your Subject line so it is more specific than "Re: Contents of cctech digest..." Today's Topics: 1. Re: ebay: VAXstations (Salt Lake City; I can pick up for you) (Zane H. Healy) 2. Re: ebay: VAXstations (Salt Lake City; I can pick up for you) (Fran Smith) 3. Re: rack mounting vintage gear (Jonas Otter) 4. Re: ebay: VAXstations (Salt Lake City; I can pick up for you) (Pontus) 5. Desoldering a chopper transistor (Rob Jarratt) 6. Re: Desoldering a chopper transistor (Pete Turnbull) ---------------------------------------------------------------------- Message: 1 Date: Fri, 6 May 2011 12:38:59 -0700 From: "Zane H. Healy" <healyzh at aracnet.com> Subject: Re: ebay: VAXstations (Salt Lake City; I can pick up for you) To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>, General Discussion: Message-ID: <p0624085bc9e9fe44266a(a)[192.168.1.157]> Content-Type: text/plain; charset="us-ascii" ; format="flowed" At 12:24 PM -0400 5/6/11, Dave McGuire wrote: >On 5/6/11 12:16 PM, Richard wrote: >>See item # 170637016956 >> >>Described as a "VAXstation 3", but I don't think that's the proper >>designation. > > That could very well be a VAXstation-3. If it was sold as a >VAXstation-II and upgraded with a KA650 CPU and MS650 memory >module(s), that'd be an appropriate designation. > > In any event, that one (he says he has two) is in the BA123 "World >Box", which have dried up significantly on the market in the past >couple of years and are becoming much harder to find than they had >been. I have a MicroVAX III, nice system. What might be interesting to know is what it has for a disk subsystem. If they upgraded the CPU's and RAM, did the also upgrade the hard drives to something other than MFM? In any case I'd say $250 for a KA650 system in a BA123 is well worth the cost, at least it is if you're local. I wouldn't want to have to pay shipping on it! Zane -- | Zane H. Healy | UNIX Systems Administrator | | healyzh at aracnet.com | OpenVMS Enthusiast | | | Photographer | +----------------------------------+----------------------------+ | My flickr Photostream | | http://www.flickr.com/photos/33848088 at N03/ | ------------------------------ Message: 2 Date: Fri, 06 May 2011 13:11:26 -0400 From: Fran Smith <fsmith at ladylinux.com> Subject: Re: ebay: VAXstations (Salt Lake City; I can pick up for you) To: cctalk at classiccmp.org Message-ID: <4DC42BBE.8080003 at ladylinux.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Hiya, > That could very well be a VAXstation-3. If it was sold as a > VAXstation-II and upgraded with a KA650 CPU and MS650 memory module(s), > that'd be an appropriate designation. I had one just like this back in the day with full graphics , mouse etc that I used as a workstation. I upgraded it from MV-11 to MV-III in box with the above kit. Nice versatile units and I hope they go somewhere they can be used. Fran ------------------------------ Message: 3 Date: Fri, 06 May 2011 20:09:02 +0200 From: Jonas Otter <jonas at otter.se> Subject: Re: rack mounting vintage gear To: cctalk at classiccmp.org Message-ID: <4DC4393E.3010304 at otter.se> Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > What exaclty is an "anti-tip feature"? > Most racks have a pull out stabilizer of some kind, or even jutting out little "feet" to prevent them> from tipping over forwards while you pull heavy things out on the rails. So, in order to pull out a > device, first you pull out the anti-tip bar at the bottom, then pull out the device. The DEC H960 > racks don't have that pull-out bar, instead they have two feet that stick out the front of the > cabinet a foot or so, and serve to trip people walking too close to the computer... > > -Ian You can see an anti-tip bar here:http://www.flickr.com/photos/textfiles/3789164168/ If you look at the bottom of the rightmost TU80 you can see a silvery T-shaped thing with a foot on it. That is the anti-tip bar. /Jonas ------------------------------ Message: 4 Date: Fri, 06 May 2011 22:34:20 +0200 From: Pontus <pontus at update.uu.se> Subject: Re: ebay: VAXstations (Salt Lake City; I can pick up for you) To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> Message-ID: <4DC45B4C.6070803 at update.uu.se> Content-Type: text/plain; charset=ISO-8859-1; format=flowed 2011-05-06 18:24, Dave McGuire skrev: > > In any event, that one (he says he has two) is in the BA123 "World > Box", which have dried up significantly on the market in the past > couple of years and are becoming much harder to find than they had been. > It is definitely on the want list :) If anyone local to me (sweden that is) has anything in a BA123 I wouldn't mind driving a bit and pay a bit for it. I've seen two in Sweden, on with GPX Regards, Pontus. ------------------------------ Message: 5 Date: Sat, 7 May 2011 10:04:40 +0100 From: "Rob Jarratt" <robert.jarratt at ntlworld.com> Subject: Desoldering a chopper transistor To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> Message-ID: <037a01cc0c95$ce2121c0$6a636540$(a)ntlworld.com> Content-Type: text/plain; charset="US-ASCII" I need to desolder a chopper transistor from a PCB in the PSU of my PDP11 so that I can test it and if necessary replace it. The trouble is that I am not experienced with soldering and desoldering and I am having a lot of trouble desoldering it. I have made several attempts, damaging one of the PCB tracks in the process (should be repairable by adding a wire). I have a cheap Weller 40W soldering iron and I have been using some narrow tips. I have one of those pumps for sucking out the molten solder. I also have 2mm solder wick (braid?). I seem to have removed most of the solder from two of the pins, mostly with the pump, the solder wick just does not seem to pick up any solder not matter what I do. One of the pins, however, goes onto a track that is more like a large area of metal and the iron does not even seem to melt the solder there. The thing I really don't understand is how you desolder more than one pin at the same time. There is always bound to be just a little solder left holding each pin in place no matter how much you remove with the pump or wick. So it seems to me that you would need to have the solder in all 3 pin holes molten, all at the same time, to be able to lift the component. What is the trick? Or is it just that my soldering iron is not good (powerful) enough? Thanks Rob ------------------------------ Message: 6 Date: Sat, 07 May 2011 10:40:55 +0100 From: Pete Turnbull <pete at dunnington.plus.com> Subject: Re: Desoldering a chopper transistor To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> Message-ID: <4DC513A7.3000405 at dunnington.plus.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed On 07/05/2011 10:04, Rob Jarratt wrote: > I need to desolder a chopper transistor from a PCB in the PSU of my PDP11 so > that I can test it and if necessary replace it. The trouble is that I am not > experienced with soldering and desoldering and I am having a lot of trouble > desoldering it. I have made several attempts, damaging one of the PCB tracks > in the process (should be repairable by adding a wire). I have a cheap > Weller 40W soldering iron and I have been using some narrow tips. I have one > of those pumps for sucking out the molten solder. I also have 2mm solder > wick (braid?). You don't normally desolder more than one pin at a time but you do need a good iron and a good pump. On DEC PSUs particularly, I've found the holes are, um, less than generous -- the component pins tend to be a close fit and there's not much room around the pin even when you get all the solder out. I normally use a 100W Weller soldering gun for things like those trannies (I have a 50W Weller temperature-controlled iron for anything else). The trick is to get the solder hot enough to flow, and to do so quickly. If you can't do that, you're unlike to succeed, and the longer you leave the heat on the pad, the more likely you are to damage something. Then use a large pump to suck it off. Sometimes adding fresh solder and trying a second time helps -- the first attempt removes most of the oxidised stuff and the flux from the fresh solder helps remove the last of it. Then push the pin from side to side to break the last whisker of solder that bridges from the pad across the gap to the pin -- if you can! I'd suggest getting a bigger iron if you can, and don't use a narrow tip for large components. I wouldn't waste any time on solder braid, either -- fine for small stuff but probably not for this. -- Pete Peter Turnbull Network Manager University of York End of cctech Digest, Vol 93, Issue 8 *************************************

13 years, 7 months

Desoldering a chopper transistor

by trag＠io.com

> Date: Sat, 7 May 2011 19:43:10 +0100 (BST) > From: ard at p850ug1.demon.co.uk (Tony Duell) >> of those pumps for sucking out the molten solder. I also have 2mm solder >> wick (braid?). >> >> I seem to have removed most of the solder from two of the pins, mostly >> with the pump, the solder wick just does not seem to pick up any >> solder not > > Thats what I tend to find too. I much prefer the solder sucker (pump). I have had similar experiences with several brands of desolder braid/wick but I have also found that the Chemtronics brand always works well for me. Unfortunately, I have not been able to find it anywhere local and always must order it from Digi-Key. I suspect it is simply a matter of being impregnated with flux, but I'm not certain. Jeff Walther

13 years, 7 months

Desoldering a chopper transistor

by tshoppa＠wmata.com

> I have had similar experiences with several brands of desolder braid/wick > but I have also found that the Chemtronics brand always works well for me. > Unfortunately, I have not been able to find it anywhere local and always > must order it from Digi-Key. > I suspect it is simply a matter of being impregnated with flux, but I'm > not certain. ChemWick (which is indeed better than the other brands but this applies to the Other brands too) will "dry out" and become much less useful If not stored properly. I suspect Digikey etc. move it a lot faster and store it more consistently than the local shops or many lesser mail order houses. If it does get dried out, dipping it in one of the fancy-pants fluxes will Pep it up considerably :-) Many of the higher-tech solder pastes and fluxes have to be stored at Even more tightly controlled temperature/humidity.

13 years, 7 months

More on telehack

by geneb＠deltasoft.com

http://telehack.com/telehack.html Documentation plus history about what it is and what it can do. Fun stuff! g. -- Proud owner of F-15C 80-0007 http://www.f15sim.com - The only one of its kind. http://www.simpits.org/geneb - The Me-109F/X Project ScarletDME - The red hot Data Management Environment A Multi-Value database for the masses, not the classes. http://www.scarletdme.org - Get it _today_! Political correctness is a doctrine, fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

13 years, 7 months

pdp11 CPU on S100 board?

by tshoppa＠wmata.com

Closest I have personal experience with, is the Alpha Micro AM100 S-100 processor that used the WD-16 aka MCP1600 chipset (LSI-11 chipset but different microcode). It is not a PDP-11 but lemme tell you, every time I see the WD chips on an AM100 CPU board it screams out "coulda been a LSI-11" to me. Working at the problem the other way: I remember a very early IMSAI product, was some sort of Unibus-to-S-100-interface. Never saw one in the flesh but it was in the IMSAI price lists. I think it was some sort of shared memory but maybe it was more than that (DMA? Doubt it but it would be nice.) Are the early IMSAI marketing docs up on the net anywhere? I think a lot of the mini-oriented stuff they listed early on (e.g. 14" SMD drive systems, 9-track systems) were vaporware but I could be proven wrong. Right now I can't even find the price lists on the net. Tim.

13 years, 7 months

ebay: VAXstations (Salt Lake City; I can pick up for you)

by legalize＠xmission.com

See item # 170637016956 Described as a "VAXstation 3", but I don't think that's the proper designation. Asking ~$250 I am in Salt Lake City and can pick these up for you if you want. I have no affiliation with the seller. -- "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download <http://legalizeadulthood.wordpress.com/the-direct3d-graphics-pipeline/> Legalize Adulthood! <http://legalizeadulthood.wordpress.com>

13 years, 7 months

pdp11 CPU on S100 board

by lynchaj＠yahoo.com

pdp11 CPU on S100 board? Given that old Soviet knockoffs of pdp11 cpus can be found on ebay, I was wondering if anyone else has thought of making S100 boards containing said processors. -- David Griffith dgriffi at cs.csubak.edu <http://www.classiccmp.org/mailman/listinfo/cctalk> A: Because it fouls the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail? -----reply----- Hi Dave, In theory, I don't see anything preventing an S-100 PDP11 CPU board. The only practical concern is there would not be enough demand for the boards to make even small batches of manufactured PCBs economical. This has proven to be the limiting factor the hobbyist projects I've seen. At N8VEM and S100computers.com, we already have about 15 or so boards including an S-100 Z80 CPU board, with a second prototype board of an S-100 68K CPU board on the way, a third prototype board of an S-100 8086 CPU board imminent, and a first prototype board for an S-100 6502 CPU board soon. So certainly there are many CPUs which can be implemented on S-100 boards as bus masters. However, these are all fairly popular mainstream CPUs and are likely to have enough hobbyist interest to warrant at least a small run of manufactured PCBs. I doubt anyone knows for certain how much demand there would be for an exotic S-100 PDP11 CPU board however I'd be willing to support a community project along the lines of the vintage-computers.com XT-IDE, AT2XTKBD, SCSI to IDE/CF, and FM Synth efforts. My role is mostly the schematic capture, PCB layout, and getting the prototype boards made. I am assuming you or someone else would have the knowledge to make the schematic and perform the initial build and test debugging. I don't know much about PDP11 since it is outside my interest area. Using the S-100 bus has some advantages in that we already have a fairly complete suite of peripheral boards already such as RAM, ROM, floppy disk, hard disk, video, serial IO, RTC/PIC, etc. The project could focus solely on making the S-100 PDP11 CPU board a bus master much like the S-100 68K CPU board already in development and just reuse the rest of the boards "as is". This has made initial build and test of our S-100 8086 CPU board *dramatically* easier. By using the S-100 EPROM board, S-100 4MB SRAM board, S-100 Serial IO board, etc the S-100 8086 CPU board booted CP/M-86 almost right away. Very nice! A community project would start with a schematic and PCB layout which should be fairly straight forward to do. Next would be getting some prototype boards which would be typically $30 each if we went the www.33each.com route $150 for 5 PCBs. If a lot of builders wanted to participate we could get a batch of 10 from PCBcart.com for probably around $250 for 10 PCBs. However, as you probably know already the track record for community projects, especially at CCTALK, is pretty poor. Probably the best bet would be to take it elsewhere to improve the "signal to noise" ratio. I am aware of another S-100 hobbyist project that is working to make a multiple board custom 32 bit RISC CPU system. It is quite impressive in scope but well beyond my skill set. Thanks and have a nice day! Andrew Lynch

13 years, 7 months

S-100 EPROM boards are here!

by lynchaj＠yahoo.com

Hi! The S-100 EPROM PCBs have arrived! These are updated respins of the S-100 EPROM board from last summer with minor corrections and improvements. The S-100 EPROM board supports a wide variety of EPROMs, EEPROMs, FLASH memories, and Static RAMs in 8 or 16 bit modes. It supports many common 28 pin and 32 pin chips. More information is available at John's S100computers.com website here: http://s100computers.com/My%20System%20Pages/PROM%20Board/PROM%20Board.htm The board is $20 plus $3 shipping in the US and $6 elsewhere. Please send a PayPal to LYNCHAJ at YAHOO.COM and I will send your boards right away! There are plenty of PCBs so even if you weren't on the waiting list there should be plenty to go around. Thanks and have a nice day! Andrew Lynch PS, I have some S-100 4MB SRAM boards, S-100 parallel ASCII keyboard interface boards, and S-100 Serial IO boards left too in case you'd like to get some of those and save on shipping.

13 years, 7 months

Enormous lot of vintage microcomputer stuff for sale (Bloomington, IN)

by chaosotter76＠gmail.com

Hello to the cctalk list after a long absence! My wife and I own a small business specializing in vintage computers and electronics, especially 1980s microcomputers and game consoles. We?re in the process of moving from Bloomington, Indiana, out to California, and as part of that move, all of our inventory has to go! Because we are anxious to complete our move quickly, we need to sell everything as a single bulk lot. If you?re a fan of the technology or looking to start your own related business, this is a chance to acquire a mother lode of great old stuff. There are some real treasures included -- we hope that you?ll be able to give these computers a good home. Included are almost 100 systems (Apple, Atari, Commodore, TI, Sinclair, and more); thousands of disks, tapes, and cartridges; over a thousand books and magazines; electronics test equipment; and more. The complete list of stuff is available at http://bit.ly/izaYpw ( https://docs.google.com/document/pub?id=1JS2fRLSfeOoI27Otf-Zhkl1f84WNZQHwM-… ) I can be contacted by email at squunkin at gmail.com, or leave a message on our Google Voice number at (408) 676-6467<https://www.google.com/voice/b/2?pli=1#phones>and I?ll get back to you. (Serious offers only, please -- and feel free to pass the word along to any interested friends!) The sale will go to the best offer from the most reasonable person as quickly as we can manage it. Here are the basic terms and conditions: - We must sell as a single lot and cannot split off individual items. This is not negotiable -- I?m in California, and the inventory is stored in Indiana. (Obviously, we can?t handle returns either.) - This is a LOT of stuff; you will certainly need a U-Haul track or the like. (I?m not a pro at this, but I?d estimate a 20? truck.) - Once the sale has been arranged, I?ll make a trip back to Indiana to help you load up your truck: you?re not on your own. This makes it very important to me to establish a firm pick-up date. I can be flexible about the day of the week. - We cannot guarantee the condition of individual items and must sell as-is: most of this stuff is at least 20 years old. We have always tried to test new equipment as it arrives, and most of the media have been kept in a controlled environment. - Southern Indiana is humid and subject to flooding, and there is a chance that some items may have some moisture damage. If we discover in the process of loading that any items of particular interest to you are damaged, we can adjust the final sale price accordingly. Please let us know about those items in advance! - The list of items we?ve compiled is not exhaustive, but represents a large sample from our inventory database. There?s more. - We currently have around 3-4 dozen WYSE and Falco terminals available, most of which power on. Please let us know ASAP if you want them included -- otherwise, they?ll be heading to recycling on May 14th. - If you have any questions, please ask! I will try to respond to every enquiry with 24 hours.

13 years, 7 months

IBM 3480 help

by pat＠computer-refuge.org

I'm attempting to figure out an error code on my IBM 3480-B22 drive, and was wondering if anyone had access to a manual listing error codes for the drives. I seem to have a "logic" manual, but that's not particularly helpful yet. The code the drive displays, immediately after start-up is "CHK 38". Pat -- Patrick Finnegan

13 years, 7 months

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test-drb May 2011