wyerd Posted January 28, 2015 Share Posted January 28, 2015 (edited) As you may know, I managed to blow the 30 year old PSU in my NOS PEB http://atariage.com/forums/topic/233880-corcomp-rs232-card-killed-my-peb-help/ and it was suggested that it could be replaced with a newer AT or ATX PC type PSU as Tursi had done http://www.harmlesslion.com/text/atx_peb.htm . I decided on the AT/LPX type which is available from Newegg http://www.newegg.com/Product/Product.aspx?Item=N82E16817338010&cm_re=at_psu-_-17-338-010-_-Product as it came with the same type of switch on my PEB and it was reasonably priced. I also ordered a Molex power extension lead http://www.newegg.com/Product/Product.aspx?Item=N82E16812196873 , a Noiseblocker fan http://www.frozencpu.com/products/8403/fan-520/Noiseblocker_NB-BlackSilentFan_X1_80mmx25mm_Ultra_Quiet_Fan_-_1300_RPM_-_10_dBA.html?tl=c15s58b160 and a Molex to internal fan connector http://www.ebay.com/itm/261510776579?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT . PSU came with 4x HDD type Molex connectors, 2x FDD connectors, the P8 and P9 type power connectors and push button power switch. Molex to fan connector. I thought it best to bench test the PSU connected to the fan to make sure that it worked before I took it apart as there were a number of reviews on the Newegg site that had DOA units. No issue with this one. I then came across my first problem. The new switch doesn't have the side mounting as the old one does, so I had to come up with a solution as I couldn't use the old one...... The power cables are soldered to the switch which unfortunately came apart. I suggest using the old switch if possible, especially with the newer rocker switch type as it saves another issue I had later on. Edited April 26, 2021 by wyerd 3 Quote Link to comment Share on other sites More sharing options...
wyerd Posted January 28, 2015 Author Share Posted January 28, 2015 (edited) I figured out that flattening out one side of the old switch bracket may solve the problem. I had to file a large chunk as it got in the way of the spring. Fitted. Would it match up with the hole in the case? Initial tests looked ok, but as the case wasn't screwed together, I could only find out once the new PSU was properly in place. Edited April 26, 2021 by wyerd Quote Link to comment Share on other sites More sharing options...
wyerd Posted January 28, 2015 Author Share Posted January 28, 2015 To be continued after lunch..... 1 Quote Link to comment Share on other sites More sharing options...
+InsaneMultitasker Posted January 28, 2015 Share Posted January 28, 2015 Nice pictures and good progress so far! 1 Quote Link to comment Share on other sites More sharing options...
Omega-TI Posted January 28, 2015 Share Posted January 28, 2015 To be continued after lunch..... Excellent so far!! I want to see how this ends! 1 Quote Link to comment Share on other sites More sharing options...
wyerd Posted January 28, 2015 Author Share Posted January 28, 2015 (edited) I had to remove the 120v out connector which also involved de-soldering the cables from the circuit board Circuit board removed I then de-soldered the fan and the Live & neutral cables. Edited April 26, 2021 by wyerd 1 Quote Link to comment Share on other sites More sharing options...
wyerd Posted January 28, 2015 Author Share Posted January 28, 2015 (edited) I then soldered the brown cable from the switch to the Neutral (the old white cable) and Blue cable from the switch to the Live (the old black cable) circuits on the board. Edited January 28, 2015 by wyerd Quote Link to comment Share on other sites More sharing options...
wyerd Posted January 28, 2015 Author Share Posted January 28, 2015 (edited) By this stage I'd removed the old PSU, fuse, fan and power connector from the PEB. I won't be going into how I did here as instructions are available on MainByte. I utilized the bolts left by the old transformer to attach the circuit board holder to. Also installed the power connector from the new PSU. Cable ties were then used to attach the board to the holder. A quick test using the case fan connected to the Molex connector. It works! Edited April 26, 2021 by wyerd 2 Quote Link to comment Share on other sites More sharing options...
wyerd Posted January 28, 2015 Author Share Posted January 28, 2015 (edited) I decided to use disconnect connectors for the power wiring to the PEB board as it'll be easier to replace the PSU in future. The PEB green and brown wires are connected together. The power from the PSU are connected to the old PEB wiring as follows :- PEB Voltage AT PSU Voltage Black Ground Black Ground Green +8v Yellow +12v Brown +16v Yellow +12v Yellow -16v Blue -12v Connected up to the new PSU wiring. I used the cables from the P8 connector. Cabled tied up. The red cables on the left are for the 120/240v switch which is tidied out of the way. Note the bent heat sink - not done by me! When the PEB was re-assembled, the question about whether the power switch would line up was answered - NO.......... To be continued..... Edited April 26, 2021 by wyerd 2 Quote Link to comment Share on other sites More sharing options...
Omega-TI Posted January 28, 2015 Share Posted January 28, 2015 (edited) Do you mind if I ask a couple of followup questions? 1) Did the switch work out perfectly after everything was all buttoned up? 2) What are you going to do with that hole from the fuse holder? Eventually jumper another holder down there or use it for another purpose like a USB power port? ** EDIT ** Never mind on question one... you posted that while I was composing my post. Edited January 28, 2015 by --- Ω --- Quote Link to comment Share on other sites More sharing options...
wyerd Posted January 28, 2015 Author Share Posted January 28, 2015 (edited) There is a plastic spacer/insulator between the switch and the metal mounting, so I figured that the newer switch is better insulated and didn't need it and without it might position the switch better. So out it came. A couple of capacitors got in the way when I re-assembled the PEB, but luckily it's flexible enough to move the obstruction out of the way. The switch is now spot on target. Once all the cards and drive were inserted back into the PEB and connected to the console, it was the moment of truth! It all appears to work.....PHEW!! This was late last night so I've still got to use it and I haven't tried the CompCard yet. I've left the fuse holder slot empty as nothings going to get inside. I may cover it with tape or leave it for extra ventilation. The fan is soooooooo quiet, I thought it wasn't on at first until I checked that it was actually spinning. Edited April 26, 2021 by wyerd 1 Quote Link to comment Share on other sites More sharing options...
wyerd Posted January 28, 2015 Author Share Posted January 28, 2015 Lessons learnt :- Don't blow the PSU in the first place!!!! It is possible to use a newer PC type PSU to replace the old one, but I'd recommend keeping the old switch by cutting the cables to the old PSU. Leave 3 inches of cable and then crimp the ends with disconnect connectors which can now slot in place of the newer switch. Quote Link to comment Share on other sites More sharing options...
Stuart Posted January 28, 2015 Share Posted January 28, 2015 Are you going to arrange some sort of cover for the new PSU board? If you have the PEB apart again and accidentally put your pinkies in the wrong place, a PC PSU can give one hell of a jolt, even if it's been switched off for a while. Quote Link to comment Share on other sites More sharing options...
wyerd Posted January 28, 2015 Author Share Posted January 28, 2015 Are you going to arrange some sort of cover for the new PSU board? If you have the PEB apart again and accidentally put your pinkies in the wrong place, a PC PSU can give one hell of a jolt, even if it's been switched off for a while. I hadn't planned on it. I'll just have to keep your advice in mind the next time I have the PEB apart. Covering it could also cause ventilation issues I would have thought. Quote Link to comment Share on other sites More sharing options...
+InsaneMultitasker Posted January 28, 2015 Share Posted January 28, 2015 Do you have any cards in the PEB without clamshells? If so, be sure the 5v regulators have heat-sinks or the higher voltage will take its toll on them. The Horizon RAMdisks, IDE card, and SCSI card are a few cards that are inserted into the PEB without shells that you may want to inspect. Quote Link to comment Share on other sites More sharing options...
wyerd Posted January 28, 2015 Author Share Posted January 28, 2015 Do you have any cards in the PEB without clamshells? If so, be sure the 5v regulators have heat-sinks or the higher voltage will take its toll on them. The Horizon RAMdisks, IDE card, and SCSI card are a few cards that are inserted into the PEB without shells that you may want to inspect. Thanks for the warning. I have the Flex Connector card, 8x32 memory and Disk Drive Interface cards installed all with shells. I still have the CorComp RS232 to install which has a thin shell. Quote Link to comment Share on other sites More sharing options...
+InsaneMultitasker Posted January 28, 2015 Share Posted January 28, 2015 Thanks for the warning. I have the Flex Connector card, 8x32 memory and Disk Drive Interface cards installed all with shells. I still have the CorComp RS232 to install which has a thin shell.The thin shell should be metal and more than sufficient. Some of the shells had spacers (plastic washer?) to contend with. I don't recall whether a metal washer is necessary to ensure full contact between the shell and the regulator "fin" containing the screw hole. If this is the RS232 that took the power hit, verify that neither the regulator input nor output are shorted to ground. You can do this by checking between ground and the input/output legs. Hopefully the RS232 didn't take a hit to a buffer chip or 9901. Others may also chime in with related thoughts, so perhaps give it a day or two before you put that card back into the box. Quote Link to comment Share on other sites More sharing options...
wyerd Posted January 28, 2015 Author Share Posted January 28, 2015 The thin shell should be metal and more than sufficient. Some of the shells had spacers (plastic washer?) to contend with. I don't recall whether a metal washer is necessary to ensure full contact between the shell and the regulator "fin" containing the screw hole. If this is the RS232 that took the power hit, verify that neither the regulator input nor output are shorted to ground. You can do this by checking between ground and the input/output legs. Hopefully the RS232 didn't take a hit to a buffer chip or 9901. Others may also chime in with related thoughts, so perhaps give it a day or two before you put that card back into the box. OK. I'll check out the RS232 card - thanks for the tip. I'll hang back a few days before plugging it in, although I may have a memory issue to sort out first http://atariage.com/forums/topic/234402-ram-errors-using-ti-diagnostics-on-extended-basic-v27/ Quote Link to comment Share on other sites More sharing options...
firepod Posted January 31, 2015 Share Posted January 31, 2015 I have been waiting to see a detailed mod doing just this, Thank you For sharing!!!!! 1 Quote Link to comment Share on other sites More sharing options...
atrax27407 Posted January 31, 2015 Share Posted January 31, 2015 The QUEST 512K RAMdisks had a pitifully small heat sink as issued. A bit of aluminum (or aluminium) sheet cut and then bent over the battery pack with a bit of clearance provided an excellent heat sink. Don't forget the conductive grease! Quote Link to comment Share on other sites More sharing options...
cbmeeks Posted October 18, 2019 Share Posted October 18, 2019 Sorry to dig up an old topic. But the images for this thread are long since gone. Is there a more modern write up to this? I'd like to use a modern PSU in my PEB if I can. This link seems to be pretty good but having a step-by-step guide with pics would be awesome. http://www.harmlesslion.com/text/atx_peb.htm Thanks! 1 Quote Link to comment Share on other sites More sharing options...
Omega-TI Posted October 18, 2019 Share Posted October 18, 2019 Dang! This was an awesome thread.. another reason to host your images ON AtariAge! 1 Quote Link to comment Share on other sites More sharing options...
wyerd Posted April 26, 2021 Author Share Posted April 26, 2021 Due to popular demand, the lost images have been located and uploaded to the thread. ? 2 Quote Link to comment Share on other sites More sharing options...
wierd_w Posted April 26, 2021 Share Posted April 26, 2021 How reliably does that AT style PSU run the PEB? 1 Quote Link to comment Share on other sites More sharing options...
+InsaneMultitasker Posted April 26, 2021 Share Posted April 26, 2021 I've been running my primary system 24x7 in this configuration* for more than twenty years. The 5v regulators run warmer, so it is important to have proper heat sinks w/thermal compound (or metal clamshell) to keep them from overheating. Stability has never been an issue, except for problems caused by the regulator heat output. The regulators ran hot at 150-175F; I typically refreshed the thermal compound, capacitors, and regulators every few years. My usage is atypical in that the only time I turned it off was to attend TI Faires/user group meetings and for the last 5 years it has operated Heatwave BBS. A few years ago I replaced the Geneve card's regulators with DC-to-DC converters. The last time I checked the converter temps they were running at about 90 degrees Fahrenheit. *I removed the PEB BUS and card cage from a donor PEB and mounted it into a mid-tower case. I did not bypass the regulators, though an earlier iteration of my system ran in a bypassed configuration. The risk (for me) was too high, in that I did not want to accidentally install a bypassed card into a standard PEB/system. 2 Quote Link to comment Share on other sites More sharing options...
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