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bettablue
March 28th, 2014, 07:33 PM
I will be rebuilding my XT's power supply, (finally) in the next couple of weeks. In particular, I need info on the coil and capacitors I will most likely have to exchange in order to get the power supply working again. Currently, it is only providing roughly 80% of what it should be delivering. There are no obvious signs of burning, no scarring, or smells of smoke, so I think the power supply's issues are really just age related.

The outer case looks great, and again, there are no obvious signs of anything amiss. It is only when I connect my trusty Simpson 260 Multi-Meter that I find anything wrong. Well, that and the fact that the XT computer will not boot. All of the voltages show the exact same thing; a full 20% lower voltage than is expected. I tested the power supply under load, and without. Same result.

Of course, any additional steps you would suggest are also welcome.

If anyone has a schematic, of can supply me a link to one, I would be truly thankful.

lutiana
March 28th, 2014, 10:40 PM
I can't help you with the schematics, but I wanted to ask you to publish the list of caps and other components you replace.

Malc
March 29th, 2014, 01:17 AM
There were a few brands of PSU used in the IBM XT's, Schrack etc, Not to mention the clones around. Probably won't be an easy task finding an exact match for your PSU if it was ever made available.

cruising
March 29th, 2014, 01:39 AM
how do you even disassemble the supply? i was trying but there was a pop clinch on it that i didnt not want to remove, and 3 screws.
Do i really need to drill the pop off? i need to clean the supply from 32 years of dust.

Stone
March 29th, 2014, 03:45 AM
It is only when I connect my trusty Simpson 260 Multi-Meter that I find anything wrong. Well, that and the fact that the XT computer will not boot.But it boots alright with another power supply, right?

ldkraemer
March 29th, 2014, 04:09 AM
bettablue,
Yes, I've downloaded several AT & ATX style Schematics. I just have to find the correct stash on the specific hard drive. It might take
a bit of searching. If nothing else I've got them on my FREENAS Server, which I'll search after April 15th.

In the mean time here is a *.txt document you can read. There is a URL on the first line where I located the information.

Also, if you aren't familiar with these Devices:
Blue ESR Meter - http://www.flippers.com/BlueEsr.html
Blue ESR Meter - http://shop.anatekcorp.com/index.php?src=directory&view=products&srctype=detail&refno=2&category=Component%20Analyzers
CapAnalyzer 88A Series II - http://www.eds-inc.com/products.html
Leekseeker 89 - http://www.eds-inc.com/leak.html
milliOHM Adapter - http://users.tpg.com.au/pschamb/lom.html
99Cent ESR Adapter - http://archive.is/301HS
ESR Info - http://www.repairfaq.org/sam/captest.htm#ctesr

I just purchased the Capanalyzer 88A Series II, to check my Kaypro II Video Board. I've got a Horizontal Line for the Video.
Shouldn't take more than a few minutes to locate the problem. Then on to the two TRS80 Model 1's and Model 4 that doesn't boot.

OH, and be sure to wire a 60 to 100 Watt Light Bulb in SERIES with your Test Power Supply AC Line (HOT). If the Power Supply is
SHORTED the Light Bulb will be BRIGHT and save you lots of Fuses and Tripped Breakers. (Then the Leekseeker will help you find
the problem part.) Watch their Video!


Larry


18023

bettablue
March 29th, 2014, 07:08 AM
I decided to answer all your questions at once, so I hope this works.


I can't help you with the schematics, but I wanted to ask you to publish the list of caps and other components you replace.

I don't have any problems with posting what I replace. In fact, I was planning to photograph and document the entire process. (Sorry, I don't feel comfortable doing video.)


There were a few brands of PSU used in the IBM XT's, Schrack etc, Not to mention the clones around. Probably won't be an easy task finding an exact match for your PSU if it was ever made available.

Thanks for sharing that info with me. In the case of this XT, it does appear to be the original PSU, but I know looks are deceiving. I don't have the computer sitting in front of me right now, but that can be remedied easily. I just have to make a trip to pick it up from Ed at his place, which I can probably do either today, or tomorrow.


how do you even disassemble the supply? i was trying but there was a pop clinch on it that i didnt not want to remove, and 3 screws.
Do I really need to drill the pop off? i need to clean the supply from 32 years of dust.

I assume you meant to say that you didn't want to remove the pop clinch. But, yes, the three screws and pop clinch have to all be on-done. However, the clinch isn't usually too awful tight.


But it boots alright with another power supply, right?

Yes, stone. I tried it once with the power supply I have in my 5161 expansion unit when I had both units here at one time. That was a while ago, but nothing else has changed.


bettablue,
Yes, I've downloaded several AT & ATX style Schematics. I just have to find the correct stash on the specific hard drive. It might takea bit of searching. If nothing else I've got them on my FREENAS Server, which I'll search after April 15th.

In the mean time here is a *.txt document you can read. There is a URL on the first line where I located the information.

Also, if you aren't familiar with these Devices:
Blue ESR Meter - http://www.flippers.com/BlueEsr.html
Blue ESR Meter - http://shop.anatekcorp.com/index.php?src=directory&view=products&srctype=detail&refno=2&category=Component%20Analyzers
CapAnalyzer 88A Series II - http://www.eds-inc.com/products.html
Leekseeker 89 - http://www.eds-inc.com/leak.html
milliOHM Adapter - http://users.tpg.com.au/pschamb/lom.html
99Cent ESR Adapter - http://archive.is/301HS
ESR Info - http://www.repairfaq.org/sam/captest.htm#ctesr

I just purchased the Capanalyzer 88A Series II, to check my Kaypro II Video Board. I've got a Horizontal Line for the Video. Shouldn't take more than a few minutes to locate the problem. Then on to the two TRS80 Model 1's and Model 4 that doesn't boot. OH, and be sure to wire a 60 to 100 Watt Light Bulb in SERIES with your Test Power Supply AC Line (HOT). If the Power Supply is SHORTED the Light Bulb will be BRIGHT and save you lots of Fuses and Tripped Breakers. (Then the Leekseeker will help you find the problem part.) Watch their Video!

Larry

18023

modem7
March 29th, 2014, 02:18 PM
OH, and be sure to wire a 60 to 100 Watt Light Bulb in SERIES with your Test Power Supply AC Line (HOT). If the Power Supply is
SHORTED the Light Bulb will be BRIGHT and save you lots of Fuses and Tripped Breakers.
But, why should bettablue do that? His PSU is not blowing fuses nor tripping breakers.

fatwizard
March 31st, 2014, 06:27 PM
Hello Thomas, I have the print you are looking for. Let me dig it out and scan it, and I'll post it here.

bettablue
March 31st, 2014, 07:26 PM
Awesome! Thanks much. That will be a great help. I know my way around a multimeter, but most of the things I've gotten from other users is on how to do something or other with my meter. The problem I have with my power supply is one of 2 items, either the coil, or one or both of the large capacitors in the AC to DC circuit (Mental block, I forgot what that circuit is called. Oh well, as long as you know what I mean.) Take your time as well my friend. I still have to get over to Ed's place to pick up the computer so I can pull the power supply for repair.

I guess you can tell by the amount of activity I've been hitting the Forums with that I have a few things in the basket. In a nutshell, I do have quite a bit going on. It all starts with a 5150 computer I'm getting as a gift. The computer will have what it needs to run, and will include a keyboard. But most importantly, it has been upgraded with one of James Pearce's Lo-Tech XT-CF Lite boards, and an upgraded 200 Watt XT power supply. The 5150 and XT-CF Lite can function perfectly fine with a standard 5150 power supply. So with that in mind, I will be playing musical Power Supplies.

I have an XT power supply in my 5161 expansion unit too, which has a bad fan bearing. Not only is it noisy, it isn't providing the cooling it needs to in order to keep from damaging the power supply itself. Then, I have a bad power supply in my actual XT machine. This is where the schematics come in. The PSU is only providing 80% across all voltages, regardless what it is supposed to be providing, the PSU is only losing 20%. Finally; I was given a power supply from an actual 5150 a couple of days ago by a friend who lives here in Vegas, and who I fairly recently found out is also a member of VCF. (The same friend also gave me a 3.5" floppy drive, and carriage assembly to add it to the 5150 when it arrives. I know it will only be able to give me 720Kb, but I figure that I'll try it out)

I think you can see what I'm doing now. With the bare PSU as a starter, I'll swap that for the 200W PSU in the 5150 gifted machine, Melora, so the 200W can be installed into my expansion unit, Alice. (I name my computers to keep things simple) The XT PSU I get from Alice, I'll open up and replace the cooling fan motor, and install it into my XT machine, Charlie. That leaves me with Charlie's XT PSU I need to repair. If I'm successful, I'll have a spare IBM 5160 Power Supply which I can then either keep in case of emergency, or I can sell to make some money to buy a couple of parts for one of my other computers. Once the new computer arrives, I should be able to do most everything in one day. Then I'll be able to take my time really pour myself into the schematics, so I make sure to buy the right parts.

Sorry Wizard; I didn't mean to get carried away again, but it always seem that no matter how hard I try, once I get my mind going when it concerns my vintage computers, I find it all but impossible to keep things short. Hope you don't mind.

Take your time putting the docs together. I can't really do much of anything until the 5150; Melora, arrives. The VCF member who is giving me the computer is assembling the XT-CF Lite, and configuring the system to make sure everything works as it should, prior to shipping it to me. From what I am told, the computer isn't much to look at right now, but it's not all beat up either; nothing a can of spray paint can't fix. There is a whole other story there too, but I'll leave that for later. I think it will be a great setup to have Alice, which is like the Ultimate refurb, and loaded with upgrades, including the expansion unit, next to a bare bones machine with nothing other than what it came with when new, including only 64Kb of RAM, and connected to a TV via RCA composite video. I think it will be a beautiful arrangement.

Anyway my friend. Sorry for writing so much in this reply. I honestly hope you have a good weekend.

Take care.

~BB~





Hello Thomas, I have the print you are looking for. Let me dig it out and scan it, and I'll post it here.

fatwizard
March 31st, 2014, 09:42 PM
Let me know if these didn't come out well, and good luck.

1807418075

bettablue
April 1st, 2014, 03:28 PM
Let me know if these didn't come out well, and good luck.

1807418075

Sorry Wizard... The only thing I get when clicking on these is a page with the image that is about the same size as what's in the thread. Seriously, they are little more than thumbnails.

If you send me a pm, I'll reply with my email address. Then you should be able to email the images to me, and I'll be able to use those.

Thanks for trying though.

ldkraemer
April 1st, 2014, 05:34 PM
fatwizard,
Would it be possible for you to enlarge the scans to 100%, and make them at least 300 or larger DPI, and post
them as a ZIP file of BMP, TIF, or GIF files, so we can enlarge, view, and study them?

Thanks.

Larry

fatwizard
April 4th, 2014, 07:45 PM
Hello all. I'm sorry to be so slow, many interruptions. I'm not sure what I did wrong the first time (some wizard). The full sized bitmaps are too big for the forum's attachment feature. If any one is interested in the files, I would be happy to send them to an email account. There are two pages and are about 7 meg apiece. Just PM me.

luvit
April 6th, 2014, 12:51 PM
compliments of fatwizard:
IMAGE1 (https://drive.google.com/file/d/0B8vJlJBkxYrfUjhCRGFXS01LQm8/edit?usp=sharing)
IMAGE2 (https://drive.google.com/file/d/0B8vJlJBkxYrfdG8zU21KNWRXX00/edit?usp=sharing)
18183

Stone
April 6th, 2014, 01:21 PM
Still impossible to read easily. Why play all these games when anyone who has access to these could post them anywhere to a file host and give us a link that we can actually use? C'mon, if you're gonna do it at least do it right. :-)

luvit
April 6th, 2014, 01:50 PM
heh, you're right about it being poor.
its weired that when i tested the results it looked good -- i wonder what i did wrong when i verified clarity after posting..
i updated with links to the original BMP images

SpidersWeb
April 6th, 2014, 01:55 PM
I was thinking "I wish these schematics showed test points and what the waveform should look like"
Then I viewed this - that's awesome - I wish more diagrams had that!

Stone
April 6th, 2014, 02:50 PM
Hey, now I can read it.... great!

Hint, when you u/l or post a pic here the forum software shrinks and compresses it which is ok for pics but sucks for things like this. :-)

modem7
April 7th, 2014, 12:48 AM
I have hosted these at my web site, specifically at http://www.minuszerodegrees.net/5160/doco/5160_documentation.htm