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Help. I shorted out my 5155's power supply.

The brown stuff is lacquer (what the wire in the transformer/filter gets coated with). It's not unusual to see lacquer there. It's quite a bit, but I wouldn't consider that to be an definite indicator of overheating.

The 5155 PSU should be able to handle the 10mhz Turbo 8088 motherboard.

The symptoms you describe could be caused by a ruptured line suppression capacitor. See the 'Line Suppression Capacitor' section of http://members.dodo.com.au/~slappanel555/failure.htm
In your photo, the two blue things are line suppression capacitors. They look okay in the photo, but take a close look at them. In my 5155 PSU, there's also one wired directly to the contacts on the power switch.

Of course, there are other components that can arc/smoke.

One way of detecting the location of arcing is to operate the equipment in a dark room, being extra careful due to the greater risk of shock (e.g. difficulty seeing opened PSU).
 
I'll add that if what you heard was a loud "snap" then just a bit of smoke, but the system kept going, it's likely a popped bypass or decoupling capacitor somewhere on one of the boards, not in the power supply. This happens more than you'd think on old gear. If it's a bypass (value around 0.1uF, don't worry about it--just make a note to replace it when you have time. If it's a decoupling (usually tantalum), move it a bit higher on your priority list, but don't sweat it.
 
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Chuck(G) said:
I'll add that if what you heard was a loud "snap" then just a bit of smoke, but the system kept going, it's likely a popped bypass or decoupling capacitor somewhere on one of the boards, not in the power supply.
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I second this. I have experienced the same multiple times. One snap, flying debris and some smoke. My S-100 backplane did this 3 times, one cap each time power was applied. The first "explosion" severed a PCB trace as well :p Look around the motherboard for signs of a broken small capacitor. Usually they are blue or light brown.

Might as well show us a large picture of the motherboard, so that we can help you look at it :)
 
QuantumII said:
Might as well show us a large picture of the motherboard, so that we can help you look at it :)
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Here's a couple of pics of the 10 mhz MB. I can't see anything here but maybe a more trained eye might see something. Also, on a side note, anyone have info on this board?
I have not been able to figure jumper settings or how to switch between turbo and slow speed. I've tried "cntrl+alt +/-", and "cntrl+alt+pgup/pgdwn" and a bunch of other keyboard manuvers with no luck, it remains in turbo mode.
 
It sounds to me like your PSU/motherboard combination is working, but that you are trying to locate the component that arced/smoked. Is that the case?

ibmapc said:
Also, on a side note, anyone have info on this board?
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Your motherboard looks very much like a PIM-TB10. The manual for that is at http://members.dodo.com.au/~slappanel555/manuals.htm

ibmapc said:
I have not been able to figure jumper settings or how to switch between turbo and slow speed. I've tried "cntrl+alt +/-", and "cntrl+alt+pgup/pgdwn" and a bunch of other keyboard manuvers with no luck, it remains in turbo mode.
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When you tried "cntrl+alt +/-", did you try the "-" on the keypad (i.e. not the "-" on the main section of the keyboard).
 
modem7 said:
It sounds to me like your PSU/motherboard combination is working, but that you are trying to locate the component that arced/smoked. Is that the case?


Your motherboard looks very much like a PIM-TB10. The manual for that is at http://members.dodo.com.au/~slappanel555/manuals.htm


When you tried "cntrl+alt +/-", did you try the "-" on the keypad (i.e. not the "-" on the main section of the keyboard).
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Yes, the combo seems to work but when Falcon AT is run, the video goes to EGA Mode(I'm using an ATI EGA Wonder) and since this game was meant to run on a 286, it pushes the system pretty hard and that's when I hear the arcing and see the smoke (happened on two separate occasions).
For now I've put the original MB back because the arcing noise made me nervous, but I'll probably try this MB agian soon. I've tried both "-" keys with cntrl+alt.
 
Looks like you've got something very close to this turbo mainboard. If the jumpers line up, you may want to fool with jumpering/un-jumpering JP6 to alter the speed.

As far as software-controllable turbo mode goes, try Ctrl-Alt-keypad anything.
 
Chuck(G) said:
Looks like you've got something very close to this turbo mainboard. If the jumpers line up, you may want to fool with jumpering/un-jumpering JP6 to alter the speed.

As far as software-controllable turbo mode goes, try Ctrl-Alt-keypad anything.
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You're right Chuck, that board looks very close. The only difference I can see is my board doesn't have JP9 for parity enable/disable. I wonder if that means that it doesn't use parity. Or, maybe it does and can not be dissabled. How can I determine if parity is used? Sorry for wondering off topic but my mind tends to do that a lot.

ps The board that Modem7 mentioned in his post also looks very close. It's manual also specifies JP6 for turbo.
 
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According to Mueller's Upgrading & Repairing PCs book, the 5155 PSU is rated at 114W. Compared to a standard 5155, you're running a faster motherboard and you've probably installed a hard drive as well. Maybe you're right. Maybe Falcon AT use is indeed pushing the PSU loading to it's limits (but not enough to invoke the PSU's overload protection).

Re the component that smoked. Have you tried disconnecting the 5155 from the mains for a while (10 minutes should be adequate), then using your nose to home in on the component.
 
modem7 said:
According to Mueller's Upgrading & Repairing PCs book, the 5155 PSU is rated at 114W. Compared to a standard 5155, you're running a faster motherboard and you've probably installed a hard drive as well. Maybe you're right. Maybe Falcon AT use is indeed pushing the PSU loading to it's limits (but not enough to invoke the PSU's overload protection).

Re the component that smoked. Have you tried disconnecting the 5155 from the mains for a while (10 minutes should be adequate), then using your nose to home in on the component.
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Yes, I've tried that but my nose can't find the source. And you're comment about pushing the PSU to it's limits is exactly what I'm afraid of. Maybe I'll put the Turbo board back in and see if I can kill it. At least at the moment I can still find refurbished PSU's. In the future, I'm sure they will be harder to find.

RE the hard drive. I have only a CF card connected to a Siliconvalley Computers IDE adapter.
 
Does your 5155 have a hard disk installed, or just floppies? If it's just a floppy system, you've got enough +5 for your board. Remember that the original 5150 PSU was only 63.5W. If you have a hard disk installed, try disconnecting it.

Your motherboard uses parity, BTW. (4 banks of 8 data bit + 1 parity).

Your motherboard is one of many variations of the basic ERSO XT board. I've got two variations here myself--an 8 and a 10 MHz one.
 
I've just calculated an approximate power consumption of the 5155's CRT unit. It's only about 15W. That's based on the fact that the unit is powered only by a dedicated 12Vdc wire pair from the PSU, the wire pair rated at 1.5A.

So if we make some approximations:
1. 5155 CRT unit = 15W
2. 10MHz motherboard = 20W (based on fact that a 5160 motherboard draws about 15W)
3. Various cards = 20W
4. CF card = 2W (a wild guess)

So Chuck is right. There's certainly enough power available.

Maybe a dud PSU - defective component that only starts to fail above a certain current level.

ibmapc said:
Yes, the combo seems to work but when Falcon AT is run, the video goes to EGA Mode(I'm using an ATI EGA Wonder)
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I should have picked this up before.
The CRT unit will be connected to the composite video connector on your ATI EGA Wonder.
What's the go there? It's set for CGA mode?
If the composite video out is switching from CGA to EGA, I bet the CRT unit is being highly stressed.
 
modem7 said:
I should have picked this up before.
The CRT unit will be connected to the composite video connector on your ATI EGA Wonder.
What's the go there? It's set for CGA mode?
If the composite video out is switching from CGA to EGA, I bet the CRT unit is being highly stressed.
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Yes the video on the internal CRT flickers alot in EGA mode, but this has not been a problem when using the original MB at 4.77mhz. Does the faster clock speed(10mhz) effect the composit out of the EGA Wonder in EGA mode? Anyone care to speculate what if any damage might be occuring with the internal monitor when the EGA Wonder switches to EGA mode? I believe it goes interlaced causing the flickering display. I was under the impression that the EGA Wonder was designed to operate in EGA mode without harming the 5155's monitor.
 
ibmapc said:
Here's a couple of pics of the 10 mhz MB. I can't see anything here but maybe a more trained eye might see something.
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Could be one of the blue capacitors. They are scattered everywhere on the board, and the one that made the pop (If one did, that is..) could just have a small crack in it making it hard to detect. On the other hand, as have been mentioned in this thread, if it works fine you should not worry too much :)
 
QuantumII said:
Could be one of the blue capacitors. They are scattered everywhere on the board, and the one that made the pop (If one did, that is..) could just have a small crack in it making it hard to detect. On the other hand, as have been mentioned in this thread, if it works fine you should not worry too much :)
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Check out this close-up of a blue capacitor. I saw the small cavity in the top of it when I inspectected the board under magnification. This capacitor is right next to the slot where the EGA Wonder was plugged in. So, my guess is that when the video board was switched to EGA mode, this capacitor didn't handle it well and started arcing ind smoking.

Now, I need to find a replacement. Printed on the side is the number 104. Anyone have any sugestions on a source for replacement.
 
It's what I said earlier--a 0.1uF bypass capacitor. Just about any type of this capacitor is suitable. I buy them by the 100s--they're cheap. You can use a film, ceramic...etc. type. It doesn't matter in this application.
 
Chuck(G) said:
It's what I said earlier--a 0.1uF bypass capacitor. Just about any type of this capacitor is suitable. I buy them by the 100s--they're cheap. You can use a film, ceramic...etc. type. It doesn't matter in this application.
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will one of these work?
 
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