test-drb May 2008

test-drb@ccmp.vtda.org

199 participants
350 discussions

Good Composite->VGA converters for classic computers (& video games...)

by derschjo＠msu.edu

Anyone out there use a composite->VGA upscaler for their classic computing and/or gaming needs? I've been looking to shave a bit of space off my workbench and just use a single SVGA monitor instead of that and an old composite monitor. I picked up one of these: http://www.amazon.com/gp/product/B000XXZQWQ and while it works great for certain systems (the C64 and NES, for example) it gets really confused by the composite signal coming from other systems (like the Apple II and Sega Genesis) and is unusable with them. Anyone have any recommendations? Thanks, Josh

16 years

sorry for the downtime

by jwest＠dewey.classiccmp.org

A list member emailed me saying there appeared to be a problem with the list. When I looked at the server I saw the usual problem, fixed it, and neglected to check further (this is a reoccuring problem that I have to "fix" every month or so). I assumed as usual this would fix the problem and was in a hurry to get out the door. Turns out, this time there was also something else amiss, so I went through a day or two of "it's already fixed" emails, only to find out it wasn't. My apologies, all should be well now. Jay West

16 years, 1 month

Funny Tek 2445 scope problem

by jefferwin＠gmail.com

I purchased a used Tek 2445 scope which works well on both CH1 and CH2. Both 10x probes check out as well. I am working on getting an rs232 interface working, if I scope the TX signal from my terminal I get a clean and synced image on the scope on both channels. All is good. I am rebuiding an IMSAI 8080. The unit I have is working well, 48K of RAM all tested, I can enter programs through the front panel and run them. Getting it to talk to my terminal program is the task at hand. Now comes the mystery. If I scope ANY bus line, chip lead on any board, I get a 60Hz sine wave that measures about 70 volts. Now, in my logical head I realize this can't be real, the IMSAI would not only not work but would be pouring smoke from every nook and cranny, bringing my wife running with claims of 'I told you so...'. So, what the hell? I have checked ground, I have checked the bus lines, I have checked the scope. I do have the active terminator card in the last slot and as I mentoned, the IMSAI works fine otherwise. Where am I picking up this 60hz sine wave? Thanks in advance! I love the fact that there are others out there that remember these great old machines and appreciate them for what they represent! Jeff Erwin

16 years, 1 month

IBM XT diagnostic ROM

by amouses＠gmail.com

Andrew et al, For some time I've seen these extremely cheap PC diagnostics cards posted on ebay Search www.ebay.com for pc diagnostic isa and you get something like this http://cgi.ebay.com/PCI-USB-LPT-Analyzer-Diagnostic-POST-Test-Cards-ISA-PC_… How about somebody get the ISA version of such a card and see if it's at all useful. I suppose it might be able to help you fault find a seemingle dead system though I am somewhat suspicious. Regards marcus. -- marcus bennett amouses at gmail.com

16 years, 1 month

OT: Low-poer real-audio player

by cclist＠sydex.com

I know this is off-topic, but I'm looking for suggestions and a solution may involve a "vintage" box. If you feel that discussion of this on-list isn't appropriate, please email me privately. Here's my situation. I like to listen to web-based radio and I transmit an FM signal so that I can listen on any FM radio. It works very well and I'm happy with that aspect. However, the system doing this is an old built-like-a-tank 500MHz P3 Compaq Deskpro box running RedHat somehing-or-the other (it's been so long since I've upgraded it that I don't remember) 24x7. I'd like something that drinks less power. Interface to the web is via 100BaseT copper. Station switching is accomplished via a simple shell script and initiated via telnet. My current thought is that I could pick up something like an HP e-PC and equip it with a CF hard drive. But a 1.7GHz CPU again seems like overkill for a very limited application. Does anyone have any other low-power ideas? Note that most of the streams I listen to are RA, not MP3. Thanks! Chuck

16 years, 1 month

Source for one-off ICs?

by trixter＠oldskool.org

I'm looking to buy 1 or 2 DS-1216e chips (they're clock chips) but am having trouble finding a reseller/distributor that will sell them in lots of less than 300. Does anyone know of a reseller for ICs that has somewhat reasonable one-off prices? -- Jim Leonard (trixter at oldskool.org) http://www.oldskool.org/ Help our electronic games project: http://www.mobygames.com/ Or check out some trippy MindCandy at http://www.mindcandydvd.com/ A child borne of the home computer wars: http://trixter.wordpress.com/

16 years, 1 month

C <-> ASM translation problem

by lehmann＠ans-netz.de

Hi, As I promissed here comes my first question ;) While writing several C files for the WEGA/ZEUS kernel out of the disassembled objects (with unresolved symbols marked as external) I came across a piece of code I can't get to reproduce when compiling C. The original object contains: 0006de: 35a2 0004 ldl rr2,rr10(#$0004) 0006e2: 9424 ldl rr4,rr2 0006e4: 0704 7f00 and r4,#$7f00 0006e8: 5d04 8000 0004 ldl $8000+$0x4,rr4 I tried to reproduce it: ipc.ip_addr.l = *(unsigned long)(uap->addr.l)&0x7F00FFFF; Which generates: 0008 35a2 0004 59 ldl rr2,rr10(#4) 000c 0702 7f00 60 and r2,#32512 0010 5d02 8000* 61 ldl _ipc+4,rr2 0014 0004* which looks for me functional the same... I also tried: ipc.ip_addr.l = *(unsigned long *)(uap->addr.l)&0x7F00FFFF; Which generates: 0010 35a2 0004 60 ldl rr2,rr10(#4) 0014 1424 61 ldl rr4, at rr2 0016 0704 7f00 62 and r4,#32512 001a 5d04 8000* 63 ldl _ipc+4,rr4 Which looks "better" but isn't the same as the original because the adress of rr2 gets loaded into rr4 first, not rr2 itself. I'm a bit lost because I tried several different */&-pointer stuff to get this as it is in the original object without success. the elements ip_addr and addr are both of type saddr_t which is declare as follows: typedef union { caddr_t l; struct { unsigned left; unsigned right; } half; } saddr_t; /* segmented address with parts */ rr4 itself gets later overwritten in both codes - my code and the original object - it is not reserved for an internal C-variable. Maybe someone from you can help me here? -- Oliver Lehmann http://www.pofo.de/ http://wishlist.ans-netz.de/

16 years, 1 month

Venner Electronics Modules

by thrashbarg＠kaput.homeunix.org

Hi, I've got here some electronic modules made by Venner Electronics LTD, Kingston By-Pass, New Malden, Surrey. One is a Transistor Decade Unit type TS.10/5 and the other just has Type TS 11/HF on it, where 11/HF is scratched into the metal label. Opening one reveals a number of Mullard OC44 Ge transistors. What on earth are they for? I can imagine they're for some sort of digital machine or even a whole computer, but I can't find any information about them or the company. Thanks, Alexis.

16 years, 1 month

N8VEM homebrew SBC PCBs

by lynchaj＠yahoo.com

Hi All, I did finally finish my homebrew SBC PCBs and made an order for several. The manufacturer says they should arrive about 5 Jun 2008 or so. If anyone is interested in building their own, please let me know. The details about the SBC are at: http://groups.google.com/group/n8vem/web/n8vem-single-board-computer-home-pa ge http://groups.google.com/group/n8vem Thanks! Andrew Lynch

16 years, 1 month

Prepare to chuckle...

by tshoppa＠wmata.com

At 6:02 PM -0700 3/9/08, Sellam Ismail wrote: >http://www.vintage.org/blog.php?action=read&pid=22 That's not bad at all compared to some of the stuff I've bought over Ebay. I've been pretty disappointed at some of the 50 or 70 pound lab instruments that look to be in perfect pristine condition before they're shipped to me - but arrived in way way too little packaging and with all the corners bashed in and knobs broken off by the time they get to me. Usually I'm so sad about the whole destruction of what was just a few days before a very nice example of 50-year-old technology that I can't even bring myself to leave negative feedback. What's the point, the seller won't learn, and history's been lost in any event. I'm even sad that I participated in the destruction (although I make it very very clear to the seller what I think he ought to do in shipping, usually the seller just takes it to the "UPS Store" and let them put it in a lightweight carboard box with some peanuts.) I'm left not chuckling but pretty depressed. Tim.

16 years, 1 month

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test-drb May 2008