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XT 5160 won't post

I

IBMAT5170

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Sep 10, 2017
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146
Location
Porter County, Indiana, USA
Took all cards out still no beep. Psu tests good voltages. Tried moving ram chips to bank zero from bank 1 and still no post. Psu does not "ground out". Just no beep and nothing on screen. Any ideas before I convert this thing to an XT/286
 
I did. I'm at a loss of what else to try. I even tried another at power supply, I'm at the point where I have purchased a 286 clone board from ebay, a multi io card, and I'm just gonna make it a 286 clone.
 
IBMAT5170 said:
Psu tests good voltages.
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So, nothing overloading the PSU.

IBMAT5170 said:
Tried moving ram chips to bank zero from bank 1 and still no post.
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You may have swapped one bad set of RAM chips with another bad set of RAM chips.

IBMAT5170 said:
Just no beep and nothing on screen.
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Many causes, with bad RAM in bank 0 still a possibility.

IBMAT5170 said:
Any ideas before I convert this thing to an XT/286
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1. Re-seat all socketed chips.

2. Thorough visual inspection.

3. A Supersoft/Landmark diagnostic ROM/EPROM (placed in socket U18) - see [here].
Example screen shot shown at [here].
It should be relatively cheap for someone to create one for you.

(Note the restriction on the types of supported video cards.)
 
I thought about searching eBay for a diagnosis rom. But I don't have an MDA monitor, nor a CGA monitor. Where I live it's very hard to come by vintage stuff organically. You either gotta pony up eBay prices or pony up Craigslist prices. Nobody ever just puts this stuff in a garage sale and recycling centers never let you rummage anymore. Goodwill's around here won't sell computers and when they do they put like a 600 dollar price tag on a commodore..

Point is.... I'm not paying 150 for a monitor. Not when I can throw in a VGA card and use what I have. People around here are sharks with this vintage stuff.
 
You need a ISA POST card to see what codes put out the motherboard. Or a logic probe to see same signal.Do not give up>
 
Not as I understand it, I'm afraid. Addressing MDA / CGA is very simple, VGA cards have more behaviours and modes, the diagnostic rom isn't really designed to negotiate its way through that. I suspect that the pc would have to pass quite a lot of the ROM's tests to have the facilities the ROM would need to wake up a VGA.

However the ROM does have a long and elaborate series of beep codes which can tell you a lot about certain kinds of problem even with no display at all, as long as your beeper is working.
 
IBMAT5170 said:
Suppose I get these diagnostic ROMs. Will they still work if I just have a VGA card
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I tried the SS diagnostic roms with a VGA card years ago and IIRC i got a screen full of garbage, It's MDA or CGA as i remember.
 
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IBMAT5170 said:
Can't I just use a CGA Monitor? Or an MDA Monitor? THe plug is the same size, and if it fits it typically works when it comes to video plugs
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If you have an MDA monitor, that is exactly the right monitor for Hercules monochrome graphics.

Don't try to use a CGA monitor, even though it has the same connector. It isn't compatible and you run the risk of damaging the CRT power supply. If you want to use a CGA monitor, plug in a CGA or EGA card to use it with. CGA cards will probably be easier to get your hands on, and easier to configure.

CGA/MDA is one of the few situations where the connector fitting is no guarantee of anything working properly.
 
I am almost certain you can't use a CGA monitor on an MDA card. The MDA video signal is on a "reserved" pin on CGA (not a signal pin) and the scan frequencies are different. "If it fits it works" doesn't seem to have been invented in the days of the original IBMs.

If you can get your hands on an MDA monitor the Hercules card ought to work fine with it. I don't think there are a lot left. A converter board to convert MDA to VGA is probably easier to get your hands on. However if you don't get a picture, with a converter board, it can take some electronics knowledge and tools to figure out if the problem is in the converter board, the graphics card, the way you connected them, or a motherboard problem. Also depending on the converter board, you may have to make up a cable to connect it. Not quite a cure for all ills, I'm afraid.

If you can get your hands on a ROM with the Supersoft/Landmark diagnostic you may well get the info you need from the beeps without needing the display to be working... whether that info leads to an easy fix or a difficult one is another matter. I don't know if anyone sells a ready-to-go ROM with the version of the diagnostic that works on the 5160, or if you'd need to get a blank and get it programmed.

PS - apologies for doubling up info others already posted - I left this half finished for a while while doing other things.
 
Does anybody here have a set of BIOS chips with the Supersoft / Landmark bios on it that I can borrow while I try to get this sorted out. After purging my bad attitude about all this I see that I gotta be so damn close! The original XT board just looks so fine and there dont seem to be any shorted Tantalums on it, I checked with a cheap-ass multimeter I picked up at an overpriced hardware store called True Value (go figure haha). Even though I rearranged the ram chips like, twice, i feel its gotta be a ram chip because what else could it be right? its not like random IC's go bad and even if they did, it wouldnt stop it from posting... right? right?
 
IBMAT5170 said:
... and there dont seem to be any shorted Tantalums on it ...
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If there were any, they would overload the power supply, resulting in the power supply shutting down (although the fan may still turn in some cases), resulting in no output voltages.

IBMAT5170 said:
... i feel its gotta be a ram chip because what else could it be right? its not like random IC's go bad and even if they did, it wouldn't stop it from posting... right? right?
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Random IC's can go bad, and some will stop the POST from even starting.

However, if you look at the list at [here], RAM chip failure is relatively common, and so it is good to eliminate it as a motherboard-no-start cause.

IBMAT5170 said:
... and where can i buy these ROM chips
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IBMAT5170 said:
Does anybody here have a set of BIOS chips with the Supersoft / Landmark bios on it that I can borrow while I try to get this sorted out.
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For the IBM 5160, you only need one ROM/EPROM, and that fits into socket U18.

If you can't get a loan of one, some people/companies that can create an EPROM hosted one for you are shown at [here]. The image that the person/company would burn into the 27256 EPROM is available via [here]. Per that site, if your 5160 has the 64KB-256KB version of motherboard, the NEC µPD27C256 is unsuitable for the task.
 
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