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286user
March 30th, 2016, 08:04 PM
I recently purchased a very good condition 1000tx. It arrived i powered it up no probs. So then i upgraded the ram to 768k, and put in a math co. Still no problems. Finally i got around to trying to install a hd in it. It was a big seagate st 225, drive with controller card. At first i put the card in, hooked up the hard drive could hear it spinning but couldnt access it from dos, let alone try to ll format it. So i read around and on the 1000's you set dip sw 2 to off to use any standard controller.
I did this put the card back in and all of sudden a saw a bright pop on the hd controller card. I immediately uplugged the machine as i could smell like something burnt. I removed the controller card and there are some areas that got so hot that it turned the solder to a ball. The next thing i did was look over the mainboard and now when i turn it on, the tx, i get nothing but a bunch of garbled information and it never goes to the memory test nor normal post.
Just to rule out the recent additions i removed, the memory upg, set the jumper back, put sw2 back to on where it was and still the same. The 286 processor feels warm as well as the co processor. Ive read about old computer power supplies taking them out, but i guess this was just a coincidence as last time i put the card and hd in, it posted booted to the a drive prompt. All i was trying to do this time was get the controller working properly and then try to low level format the drive so i could install windows on this old computer. If its something with the power supply i do have another tandy a sx laying around with a good ps in it, well it worked last time i booted it, and could try swapping to it to see if that makes a difference. But i did check around the board and nothing seems blown, swollen, or burnt. I even smelled near the ps area and it was ok, only the controller board i removed had the burnt smell and balled up solder on it.

Thanks in advance.

mojorific
March 31st, 2016, 10:08 AM
Wish I could give you an easy answer. I see you read this:

'The 1000SX, TX, SL's, and TL can use most standard 8-bit hard drive controllers. The SX and TX will need DIP switch 2 on the motherboard turned off to allow the hard drive to use IRQ 5 as is standard for XT-class systems. The Western Digital WD1004 will not work in the SL or SL/2. Otherwise, most any MFM or RLL controller will work.'

There is also reference on the radio shack site:

Switch S-2:

#1 OFF Selects composite monochrome monitor
ON Selects color RGB monitor (standard)
#2 OFF Disables on board interrupt 5
ON Enables on board interrupt 5 (standard)
#3 OFF Disables on board interrupt 6
ON Enables on board interrupt 6 (standard)
#4 OFF Disables on board interrupt 7
ON Enables on board interrupt 7 (standard)


Perhaps you weren't looking at the motherboard right when you flipped the jumper, and ended up flipping one that did not have the desired result?

http://support.radioshack.com/support_computer/doc1/1276.htm

Hard to tell what you can do to fix the problem now. I don't imagine the problem is power supply related, since you are getting a video signal.

I have a TX unit myself that functions well, and perhaps I could get a copy of the bios for reflashing if you manage to get that far. You may try replacing the ram to see if that fixes the issue as well. The message displayed right now seems to indicate an address error, but the text is garbled as well that may be a result of something blown on the motherboard.

keenerb
March 31st, 2016, 12:15 PM
It was probably a tantalum capacitor. Those can short when they blow and damage other components pretty easily. Does the on-screen text respond to keypresses or scroll or anything like that? Does the computer seem to boot up (floppy drive reading and all that)? Unfortunately I don't know have the slightest idea what that might have damaged.

Maybe a piece of hot solder landed somewhere on the motherboard and is currently causing a short, look over everything REALLY carefully.

T-R-A
March 31st, 2016, 03:13 PM
Are you certain the "balled-up" areas you speak of weren't there to begin with. What you appear to have is just solder reflow from the bottom of the board to the top which occurs during the solder-reflow process on areas that are unpopulated, especially near the edges of boards (i.e.---the missing R17-R23 & R25-28 ). It's normal to look like that on areas that don't have components stuffed into the vias. I'd suspect (as mentioned) a shorted/blown capacitor first.

retrogear
March 31st, 2016, 03:28 PM
I agree with TRA. I don't see anything in your photo. Could a tantalum cap have blown on the motherboard near where you saw the flash? The cap could have sprayed up onto the card to give it a smell.

keenerb
March 31st, 2016, 03:37 PM
You are booting WITHOUT the drive controller installed, right?

(edit)

And yeah, nothing on that pic looks particularly troublesome.

Here's a pretty high-res photo of my 1000TX motherboard, look over yours and see if you have anything missing or damaged.

If there was a flash you'll probably find one of the little orange blobs has evaporated.

http://i.imgur.com/j1LlM6z.jpg

Half-Saint
March 31st, 2016, 11:27 PM
I had a tantalum capacitor blow up on one of my ISA VGA cards but it still works :-)

retrogear
April 1st, 2016, 03:03 AM
Jeez keenerb, nice picture !! I see a 5V regulator in the back by the slots which would be a candidate for failure if a cap blew or a card popped. Most of those caps are just noise filters on the 5V lines.
If you found one popped you could just snip it to test temporarily. Of course, don't put any cards back in until your motherboard is functioning normal. If you have a meter, verify the 5V on that regulator too.

keenerb
April 1st, 2016, 04:24 AM
Jeez keenerb, nice picture !! I see a 5V regulator in the back by the slots which would be a candidate for failure if a cap blew or a card popped. Most of those caps are just noise filters on the 5V lines.
If you found one popped you could just snip it to test temporarily. Of course, don't put any cards back in until your motherboard is functioning normal. If you have a meter, verify the 5V on that regulator too.

LG G4 does take a nice picture. You can almost read the numbers on the smallest parts.

I'm disassembling and taking detailed photographs of my Tandy collection as I actually collect them. So far I've gotten a TX, SX, and TL. RL is in the mail and I'll be keeping an eye out for an HX/EX coming up soon.

I really wish I could find an RLX, that's my Tandy holy grail... :(

wesleyfurr
April 1st, 2016, 06:24 PM
Good luck with your collection! I've been working on collecting Tandy's as well. My first computer as a kid was a 1000SL. Problem now is prices and shipping keep going up...so far I've not spent more than about $50 on any of them...and obviously getting to the harder to find models...though I think I have snagged the most rare...the 1000AX and PC-1000 (no-name SL clone made by Tandy). Here are photos of most of my 1000's:

http://www.megley.com/photos/tandy

Need to add photos of the HD, TL/3, and EX...and some of the non-1000's. Do you have photos of your posted somewhere online?

Wesley

286user
April 4th, 2016, 11:19 PM
ok been busy, but @keenerb, no unfortunately the msg stays on screen and never progresses past it, i also tried hitting enter or any other key on the keyboard and its just stuck there.
@t-r-a, the "balled up solder" is on the expansion card controller. As far as i know and im real certain, prior to this it was flat and basically a filled in hole on the card, not balled up. When this did happen that night, i noticed looking up from above as i turned on the unit, a flash from the card itself and the smell of burnt electronics, so i immediately cut the power and removed the card.
Overall ill probably upload a full or set of zoomed in images of the board once i compare it, I need to remove the board to do so and will try and examine it to see if i see anything burnt or what not.