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Error on recently rescued Sperry PC

L

Legodude522

Member
Joined
Mar 19, 2006
Messages
24
Location
Austin, TX
Hi all. I recently rescued a Sperry 3070-02 PC clone out of junk store in Freeport, TX. I finally booted it up today with a screen attached and got an error message that I'm not familiar with.
E-TD10
TOD ERROR
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Has anything seen this before? I have a hunch that it could be clock related. The only thing I really know about this machine is that it has an AMD D8088-2, Miniscribe HD, and a 5.25" floppy drive. There is also a slight burning smell emanating from the machine but that could just be dust. I suspect if it was a capacitor, I'd know.
 

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Thanks for the input. I did find a battery soldered to the board and it does look like it is corroding. I'll need to pull out the soldering iron for this one.
sperry_battery.jpg
 
Legodude522 said:
I did find a battery soldered to the board and it does look like it is corroding. I'll need to pull out the soldering iron for this one.
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I don't see any corrosion in the pic.

Even if it is corroded removing it is probably not going to make any difference at this point.
 
The error message may simply mean that the time of day hasn't been set (you wouldn't expect the clock to keep running after years of storage, would you?). The RTC chip is an Oki M5832, so one of the clock utilities posted on this forum should work to remedy that situation.
 
Chuck(G) said:
The error message may simply mean that the time of day hasn't been set (you wouldn't expect the clock to keep running after years of storage, would you?). The RTC chip is an Oki M5832, so one of the clock utilities posted on this forum should work to remedy that situation.
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I'm unable to do anything else. Computer boots up to that error and doesn't let me go pass it. Not sure if I'll be able to run the utility. I'm currently without means to download and write stuff to floppies. I might have to go back to this.
 
A little google-fu shows that this system (Sperry 3070) was made by Mitsubishi (like the Leading Edge machines) and has some peculiar customization. One user reports that the DB25F on the rear panel may look like a printer port, but it's really an RS232C port--I can't make out the part number of the ICs close to it because of the dirt.

At any rate, the box is supposed to be 100% PC XT compatible (with a "turbo" setting), so worst case, you may have to resort to plugging in a generic BIOS to get things to go. In the meantime, you might try removing any cards not related to basic function and seeing how far the boot process will go.
 
Whatever you do, don't discard it -- I believe that model, if you have the color monitor, used an interesting extended CGA card that could display 256 simultaneous colors. The color monitor, IIRC, was an interesting "slow phosphor" model (ie. like a slow phosphor 5151 MDA monitor, but in color). It is a fairly rare system.
 
Trixter said:
Whatever you do, don't discard it -- I believe that model, if you have the color monitor, used an interesting extended CGA card that could display 256 simultaneous colors. The color monitor, IIRC, was an interesting "slow phosphor" model (ie. like a slow phosphor 5151 MDA monitor, but in color). It is a fairly rare system.
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Did not get a monitor with it. The monitor that was with it when I pulled it out of a pile of junk was VGA with most of the pins smashed on the connector. I can only deduce that they tried pushing it into the CGA port. :evil: Currently using it with my 50" LCD TV.

Progress so far...

I replaced the battery just to see what would happen. Burning smell went away, probably because I replaced the battery. Now it powers on, cursor flashes once, and then restarts. It could be because I unplugged all of the cards and plugged them back in. The ISA port contacts look oxidized. I tried doing process of elimination with the cards which I think narrowed it down to either the memory expansion card or the graphics card.
 
OP: any progress with your Sperry PC HT? I have the same error message after getting the machine out of storage a couple days ago.
 
I never did quite get past this. I tried a rechargeable lithium battery that I had handy and no luck. I haven't tried a direct replacement battery on it.
 
The computer should still run without a battery...

You mentioned there was an area of corrosion? Are any traces damaged in that area?
 
My board looks pristine without any damage as can be seen here: https://drive.google.com/file/d/1EivfCJdLwdnEPcx9NiT12BoVghCPYpMO/view?usp=sharing (including a link to a high resolution pic).

I think the error has something to do with power supply issue. I have measured on each TTL chip's VCC and GND pins close to 4.5V when the computer is on. That is a bit low considering TTL VCC levels lowest value is around 4.75V. The power supply does have a 5V adjust pot but turning it fully clockwise only increases the VCC rail to only 4.6V. It could also be a bad chip that is loading the power supply since without load the power supply's 5V does measure good.

I will continue my troubleshooting but it is very difficult without schematics.

Edit: I Just got schematics from one generous forum member the schematics for the Leading Edge Model M computer. Hopefully the schematics match with Sperry PC HT 3070-02 that I have.

FYI the error message on my monochrome monitor:
23.jpg
 
Could the Sperry owners in this thread please dump and post their BIOS ROMs? Pretty please :cool: I'd like to add them to the MAME emulation.
Robert
 
rfka01 said:
Could the Sperry owners in this thread please dump and post their BIOS ROMs? Pretty please :cool: I'd like to add them to the MAME emulation.
Robert
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and If anyone gets around to doing this, I wouldn't mind seeing dumps of the video character-generator ROM either, for my oldschool PC font pack. :)

Though I'm mostly interested in knowing more about that rumored 256-color CGA, and/or that mono card (if they're not the same board!) Looks like it's an interesting little system.
 
The 256 colors are real, but IIRC it's a palette of 256 of which you can display 16 at a time. I last saw it in operation in 1985. The color monitor was more interesting: It used slow phosphors. So, try to picture a monitor with monochrome phosphor persistence, but in color.
 
Trixter said:
The color monitor was more interesting: It used slow phosphors. So, try to picture a monitor with monochrome phosphor persistence, but in color.
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Intriguing - gotta wonder if that was their secret sauce for achieving those extra colors. Temporal dithering like today's el-cheapo flat panels, but without the visible flicker due to the long persistence...
 
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