Title: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: HideawayStudio on August 20, 2009, 03:41:46 PM UPDATED:
For those more technically minded who want to fault find or even look into replacing their PSUs with something a little more modern/reliable here are some details on the EII's supply rails to the main PCB assembly connectors and drives. There are two types of PSU wiring harness found in EIIs which connect to the 8 pin PSU output header J101. One is identified by only single wires going to each crimp on the output header connector and the other by there being two wires ie. the harness is daisychained to the same header using an IDC header connector. The pinout is the same BUT the colour code is slightly different and on the single wire crimp version there is no orange wire in position 7. J101 pin: Colour: O/P Voltage: Usage: Notes: ============================================================= 1 Red +13.4 volts Analog +ve rail Linear post regulated - low current 2 Yellow +5 volts Digital 5V Switch Mode - High Current - CPU/Logic 3 Yellow +5 volts Digital 5V Switch Mode - High Current - CPU/Logic 4 Green 0 volts Return 5 Green 0 volts Return 6 Blue or Purple 0 volts Return 7* Orange +12 volts Digital 12V Switch Mode - High Current - Disks 8 Black -15 volts Analog -ve rail Linear post regulated - low current * Note: This wire is not present on single crimp harness connectors. I have yet to determine the supply currents but I suspect the analog rails are <2 amps and the 5 volt rail at least 15 amps!! The 12 volt rail will be fairly hefty too. Both Green and Blue/Purple returns appear to star earth in supply and are very much connected together as far as I can see in the PSU schematic. A combination of a 12/5V 150W switcher and a +/-15V linear PSU chassis would probably work well in this application. I will post more when I get a chance to poke around again in my EII. BE VERY CAREFUL OPERATING EII WITH THE TOP CASING REMOVED - THIS PSU BITES ALONG WITH THE BACK OF THE IEC SOCKET, SUPPLY SELECTOR SWITCH AND FUSE HOLDER. THE PSU ITSELF IS FULL OF HIGH VOLTAGES AND PRODUCES A SIGNIFICANT OUTPUT CURRENT WHICH, IF SHORT CIRCUITED, COULD CAUSE SERIOUS DAMAGE TO YOUR SAMPLER - OR YOU!! THE ABOVE NEEDS VERIFICATION - BY OTHER OWNERS!! Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Chaztech on August 20, 2009, 04:02:53 PM Thanks Hideaway! good information!
Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: dr.c on August 21, 2009, 02:25:21 AM Sorry, but it would have been great if you could have given the pin numbers with the corresponding colors and the voltages. For example, if one gets the connector dissassembled, its impossible to rewire it with these infos. For example, there is an empty place, and as well, two yellow and two green connections.
Does the connector you have correspond to the picture below ? It seems that there are TWO KINDS of wiring ! Thanks in advance Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: HideawayStudio on August 21, 2009, 08:01:11 AM Sorry, but it would have been great if you could have given the pin numbers with the corresponding colors and the voltages. For example, if one gets the connector dissassembled, its impossible to rewire it with these infos. For example, there is an empty place, and as well, two yellow and two green connections. Does the connector you have correspond to the picture below ? It seems that there are TWO KINDS of wiring ! Thanks in advance Very good point Dr.C - yes I've gotten the impression there are two PSU's and harnesses for a while now. Between us I think we need to determine the changeover date/serial number range for each and how to identify them. My EII is an earlier EII ie. not a an EII+. Unfortunately my S/N has worn off the label with age but I will checkup the manufacture date. I will take a picture of my PSU harness connector similar to yours. The concern is that the colour codes are different too. It is highly unlikely that the voltages are different - just the connectors and colour codes. I have modified the original post with details for both variants - I would feel happier though if more owners could verify this table. Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Chaztech on August 26, 2009, 02:09:37 PM Hi Dr.C, Hideaway,
I have 5 EII's and the wiring is the same as your picture. On a working unit i Measured red 13.13volts yellow +5.0V greens ground empty space +14volt positive the black -14.00volts Blue line gave me nothing could be AC maybe? I will check the schematics i have and confirm. remember these color codes are opposite a typical 3.1/4 floppy red and yellow are reversed! i fried a floppy before i realized it. the mounting kit had a power adapter plug for the 3.25 floppy the power positions are incorrect for the emulator but this can be easily remedied by swapping the pins on the adapter plug. regards! Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Zomnius on February 11, 2010, 01:33:06 PM 5 eII's ??
We like to see some pictures of that don't we? Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Elmbeatz on February 18, 2010, 02:45:57 AM yes!
Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Zomnius on February 21, 2010, 01:40:53 PM pics please........5x EII - heaven!
Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: dr.c on March 09, 2010, 01:24:30 PM The buffer is full, I cannot send docs.
sent me your email adress at : dr.c@keyboardsrecording.fr I will mail the docs Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Drone on September 04, 2010, 06:03:08 PM Hi Dr.C, Hideaway, I have 5 EII's and the wiring is the same as your picture. regards! Piks Please ! Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: erwinIII on March 22, 2011, 05:55:06 AM does all the info about wiring hideaway posts also exist for the EIII keyboard ?
Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: ryansupak on December 05, 2011, 01:04:43 PM Has anyone successfully replaced the PSU in their unit?
rs Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: FairlightCMI on January 11, 2012, 05:17:37 PM Hideaway...thanks for the great info.
Does anyone know if the 2 types of EII psu's are interchangeable? I have 2 EIIs with one of each type of PSU. (One with the 2 cables per pin at J101 and one with a single per pin) I would like to swap them out for troubleshooting purposes. Can that be done without problems? Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: DARKSHINE on April 05, 2012, 10:40:46 AM I make the test of tension of power supply
If I test it to the outside of the box I am forced to disconnect the two connectors Voltage 110/220 What is the voltage in this case the original that I must provide 220v/110v I think my Emulator II + original EUROPEAN Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: DARKSHINE on April 05, 2012, 10:42:32 AM Connector which are connected to Selector control voltage 110v/220v
Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: HideawayStudio on June 13, 2012, 01:15:07 PM I make the test of tension of power supply If I test it to the outside of the box I am forced to disconnect the two connectors Voltage 110/220 What is the voltage in this case the original that I must provide 220v/110v I think my Emulator II + original EUROPEAN When the two wires to the 110/220 selector switch are disconnected, the PSU is setup for 220V operation. Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: dr.c on July 12, 2012, 05:09:21 AM False, it explodes !
Too bad... Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: HideawayStudio on July 19, 2012, 12:51:09 PM False, it explodes ! Too bad... What?? The PSU is without question set to 240V with the voltage selector wiring removed - mind you - I have to admit those EII PSUs have a habit of going up just looking at them - they're 'orrible!! Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: DARKSHINE on December 28, 2012, 11:05:50 AM I find this: http://www.synther.org/emulator2.html
a new power supply with a fan ! ! ! ! ! If you find the model which was used to make I read T-... ? Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: ddvdave on February 05, 2013, 07:10:08 PM I find this: http://www.synther.org/emulator2.html I think I found it -- it looks like it's a MW (MeanWell) T-60C. See here: http://www.meanwell.com/search/T-60/T-60-spec.pdf -Dave Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Elmbeatz on March 26, 2013, 04:26:35 AM Cool!
Can someone tell the difference between T60-C and T60-A ? EDIT: Sorry, found it. Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: who on April 03, 2013, 06:45:55 AM I reached out to Carlos, the Technician who performed the power supply replacement mentioned here:
http://www.synther.org/emulator2.html He shared the following info with me: The EII in my website is not mine, it was a repair for a customer, the same than the other machines listed. "I installed a "Mean Well T-60C" (http://eu.mouser.com/ProductDetail/Mean-Well/T-60C/?qs=V9a8iPeg90zlDGU%252btuqvCw==), which generates 5V at 5Amps, +15V at 2Amps and -15V at 0.2Amp. This requirements are very basic in switching PSU's, you will easyly find a PSU with that power and voltage arrangements. This one was about 50€ in the shop I bought it. The replacement is straight forward but you may have to make new holes in the subchassis for attaching the new PSU. The connections depend on the PSU you use, but generally they are screw terminals. Feel free to copy this text in the thread Best regards, Carlos." Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: kdk on April 03, 2013, 09:39:57 AM I installed a Meanwell T-60C and it appears to be working well. I don't have any floppy drive in it, just a HxC Rev. F, so I don't need a 12V supply line.
I think the price for the PSU is about $35 plus shipping from Jameco.com. Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: who on April 06, 2013, 08:09:24 PM I just installed a T-60C in my EII and all of the problems appear to have gone away. Thanks to Carlos and others for their help!
(One of the strangest problems was with the first fader/slider: The effective range kept getting shorter and shorter. I bought replacement sliders, but no need to install them now. Update: I was wrong, the slider started acting up again, but all the other problems have gone away since installing the new power supply.) Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Elmbeatz on April 16, 2013, 01:41:25 AM Would a MeanWell T40-C also work?
Greetz, Elm. Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: lunatic on April 16, 2013, 05:58:05 AM The T40-C might not have enough WATT to power the EII. T-60c supplies 62.5W, the T-40c only 40W...
Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Elmbeatz on April 16, 2013, 06:55:03 AM Thanks for replying!
The T40-C might not have enough WATT to power the EII... Is that for sure? May I try it out nevertheless without harming the baby? Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Elmbeatz on April 17, 2013, 01:41:34 AM Anybody?
Dr. C ? :-[ Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: kdk on April 18, 2013, 06:58:18 AM The T40-C might not have enough WATT to power the EII. T-60c supplies 62.5W, the T-40c only 40W... I just powered up my EII with the Meanwell T-60C PSU in it and it draws 48-50 Watts. That's with a HxC and no Floppy or hard drive in it. The T-60C is rated for 62.5W. Perhaps the Meanwell TP-75B would be a better choice? It's rated at 75 watts which would give a bit more headroom. Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Elmbeatz on April 18, 2013, 07:10:13 AM I see.
Well, I shot 4 of those T40Cs for just a bit of money, so... Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Elmbeatz on April 19, 2013, 07:13:57 AM Would it be possible to fit in TWO of the T-40Cs (chained), to seperately supply the drives?
Greetz, Elm. Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: lunatic on April 19, 2013, 07:41:34 AM technically yes and form what i've seen, it should not be a problem with space either... Just heat development could be critical.
Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: kdk on April 19, 2013, 09:31:11 AM How would the two PSUs stay balanced so that one doesn't run at 100% output and get burned up?
Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Elmbeatz on April 19, 2013, 12:18:10 PM How would the two PSUs stay balanced so that one doesn't run at 100% output and get burned up? ??? ??? ??? I have no idea, I am no tech, that's why I ask those 'stupid' questions... ::) Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: lunatic on April 20, 2013, 06:49:07 AM How would the two PSUs stay balanced so that one doesn't run at 100% output and get burned up? ??? ??? ??? I have no idea, I am no tech, that's why I ask those 'stupid' questions... ::) If you can determine which line pulls which wattage it should work. Anyways i would not mess with the EII on this delicate level just to save a few bucks... Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: who on April 28, 2013, 07:53:32 AM UPDATE: Regarding my T-60C install, I think I have a heat build-up/thermal issue. Has anyone experienced the same?
I'm going to install a low-noise fan next to the supply and see if that helps. Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: logiclust on May 14, 2014, 08:52:13 AM I just looked into getting one of these Mean Well 709-T60C for my eii and they've been discontinued. figures. anyway, I wanted to know how/if they're still working for you guys? i plan on still running 1 floppy drive along with an HxC that i just ordered. I'm pretty sure i can find another replacement i if i use the MW as the spec.
Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: who on May 14, 2014, 09:01:43 AM No problems and please ignore my previous post in this thread. I don't remember what the fix was, but I did not install a fan.
On a related note, I installed a different Mean Well supply in my emax and no problems thus far. Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: logiclust on May 14, 2014, 09:07:19 AM Cool, thanks Who,
another thought… the t-60 has no 12v, correct? this is required for floppy operation, correct? Am i mistaken or would i need to find a ps that has a fourth +12v output in order to run my floppy? cheers, -t Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: kdk on May 14, 2014, 12:04:33 PM Correct - the T-60 is +5V, +15V, and -15V only.
I have been running my EII with no floppy, just an HxC in it and the T-60 is still working well. I've not had any overheating but then I have a hole where the second floppy would go so it gets good ventilation! I did buy a second, smaller Meanwell with +12V (and probably +5V as well, and I have yet to try and get a floppy installed. I was just going to tie the grounds together on them and not worry about the +5V on the second supply. Perhaps some day I'll install the floppy, but I have a Kyroflux on the PC with a Panasonic 5 1/4" drive that I read old floppies with and then just move everything on to the HxC. Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: logiclust on May 15, 2014, 01:44:44 PM fantastic, thanks for the tips! I'll let you know what i end up finding
Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: kdk on May 16, 2014, 10:59:05 AM No problem!
I just bought a box of 100 EII floppies so I think I'll try getting that second Meanwell PSU piggybacked in with the first one and see if I can get the floppy running again. I think I had some issue with the jumper settings on the EII floppy as well - does anyone have that info? I've Panasonic and the original Shugart drive we well. Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Gregory on January 23, 2015, 06:08:01 AM I'm currently looking for an alternative replacement PSU, which would also provide +12v line for both disk drives.
As far as I understand, the original EII PSU provides two Switch Mode output lines (+5v, +12v), but the other two lines (+13.2v and -15v) are linear post regulated (for the analogue circuitry). But is it possible and safe to use a PSU, which only provides Switch Mode outputs - even for those two lines for the analogue circuitry? I can see from the forum that other users successfully use Mean Well T-60C (it only lacks +12v line for disks), but it seems that T-60C provides all three outputs in Switch Mode. Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Elmbeatz on March 15, 2015, 08:16:22 AM Hi!
I'm just about to install a Meanwell T-60 C in one of my EIIs. The connectors on the powersupply are: Mains L,N, Ground, -V, +V, COM and +5V. One question: Where do the blue and green "0V Return" cables have to be connected to? Thanks for answering in advance, Elm. Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Elmbeatz on March 15, 2015, 02:27:13 PM Solved - the have to go to "COM".
Installation done - WOW. Next I have to source a good replacement display and find courage to also install that. Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: ahaigh01 on June 01, 2015, 05:33:56 PM Has anyone come up with a working solution for the lack of 12 volts of the Meanwell T-60? I have bought a T-60 but haven't done anything with it yet because I don't have an HxC, and I will need my floppy drives to boot from. Thanks for any advice.
Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: ahaigh01 on July 27, 2015, 09:52:23 AM Success with the installation of the MeanWell T60-C. It brought the EII back to life. I was not able to get the original 5.25 floppy drives to run, although I did get a 2nd 12 volt MeanWell power supply and made the attempt. I think it was to do with the 2nd 12 volt supply not having a 'com' connection like the T60-C does. Apparently there is no info on getting the original floppy drives running with a T60-C, so I abandoned the idea and bought an HxC, which works on 5 volts alone.
Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: moellhoven on September 16, 2015, 02:45:36 AM Hi guys,
need a little help with my Emulator II. Found my broken EII for a bargain and finally have some time to try to fix it. Got the Mean Well T60C and put it in place of the old PSU. It is an early revision serial #242 that has the single wire harness with no cable on pin7. I was wondering where does the 12V come from to power the disk drives. If the description in the first post is correct it does not come from the PSU. Was measuring at the power connector for the disk drive and there is +15.5V and +5V present. It is fine to run the drive at +15V? Another question is it fine to run the Analog Circuit at 15V instead of the specified 13.4V? Good news is that EMU greets me now with the Insert Diskette... display. Still have to get a floppy emulator. Attatched are the pictures before and after PSU installation. Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: ahaigh01 on September 16, 2015, 06:42:02 AM Hi moellhoven,
Congrats on getting the EII to power up! I'm not a tech, but I managed to get my EII repaired with a T60C and an HxC Read above for more info on the 12 volt problem. The T60C can't supply it, so in my case I just got the HxC and removed the old drives. I haven't seen a solution for running the original drives with a T60C posted anywhere. Apparently running the analog circuit at 15V is not a problem because that is how everyone is doing it. Good luck, and let us know how you make out.. Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: moellhoven on September 16, 2015, 08:57:29 AM Yes, i understand that the T60C does not supply 12V.
But i wonder how the old PSU did it when there is no connection on the harness carrying the 12V? Good to know that 15V is fine for the analog circuit! Anyhow just connected the drives for testing and these seem to run at 15V too. Can't be sure cause i mostly get disk errors but i am able to load the system from one of the disks. Could be that either the drives or disks are just in bad shape or maybe 15V is not fine for the drives? Did a quick test run of the machine and did some sampling and messed with the filters, envelopes and loop parameters. I think one of the SSM2045 is faulty cause there is no filtering on one voice. The other issue i found is that the machine freezes when the hood is closed. Otherwise the EII seems fine at first glance. Will do some more troubleshoothing tomorrow but i am happy that the beast is mostly running again. Any tip where to get the adapter cables and 5.25 to 3.5 drive bay for the HXC floppy emulator in europe? cheers :) Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Gregory on September 16, 2015, 04:37:06 PM The floppy disk drives can handle not more than 13.2 V. This is the maximum. The nominal is 12V. Anything higher than +13.2V will damage the drives.
According to the drives specifications: +12V plus/minus 10% http://hxc2001.com/download/datasheet/floppy/thirdparty/Shugart_Associates/SA455%20SA465%20Minifloppy%20drives.pdf Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: moellhoven on September 17, 2015, 02:45:04 AM Thanks Gregory. Will be patient for a couple of days until the floppy emulator is installed.
Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Electro disco club on November 14, 2015, 06:44:56 AM Hy people.
could you please post photos of your new improvement and ideas please? did you find solution for old disk drive with a 12V +-10% WHAT IS it? i don't have this on my psu? see picture attached Thanks Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: moellhoven on November 14, 2015, 07:41:40 AM Hi,
this is just a Fuse holder. On my EII there was a piece missing in the standard one. I have no solution for the floppy drives and run my EII with just a HXC floppy emulator and it works great. As an update on my progress. I was lucky that the SSM in my maschine was fine. Just had to replace a shot multiplexer. Everthing works pretty good now. Only problem left to solve is a high pitched background noise around 5k that appears sometimes. Especially with self sampled material. Could not figure this one out yet. Otherwise i am happy and really like this machine! Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Elmbeatz on November 17, 2015, 08:36:05 AM .... Only problem left to solve is a high pitched background noise around 5k that appears sometimes. Especially with self sampled material. Could not figure this one out yet. Otherwise i am happy and really like this machine! Hi! Try to connect your EII to another power outlet. I also had that high pitch noise which drove me nuts.... User "Meastempo" came up with the suggestion and it worked for me. here's the thread: http://eiiiforum.com/index.php?topic=2794.0 (http://eiiiforum.com/index.php?topic=2794.0) Greetz, Elm. Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: moellhoven on November 17, 2015, 11:09:57 AM Brilliant :)
Thank you for letting me know. Will try this out on the weekend! cheers, André Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Gregory on August 03, 2016, 04:02:43 PM Hi!
There is a Power Supply, which can be used in an Emulator II as almost direct (but much better) replacement instead of the factory installed PSU. It will be necessary to adapt the Emulator's power wires for the new PSU, of course. It is called Condor "GPM80C" (Medical Grade version, especially recommended) or "GPC80C" (regular version). This PSU has all the necessary lines, including +12V line for the Floppy Disk Drives. Instead of +13.2V line, there is +15V line. You can find the specifications here: http://www.slpower.com/data/collateral/GPC80_DS.pdf Seems like it was discontinued several years ago, so if you obtain this model - you will have to ask a technician to replace all electrolytic capacitors on it (preferably by Nichicon branded capacitors, just like the original caps). There is a seller on eBay, who has several of these PSUs. After installing this PSU (or any other PSU, which has +15V instead of +13.2V) you will have to re-calibrate Pitch and Mod Wheels, because both wheels use +13.2V line, which now will be +15V. Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Electro disco club on January 21, 2017, 12:54:35 AM I ve found one T60C on eBay from england.
Here is my installation thanks to the forum. i had change the pin ID from the hxc. it's great Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Paula on June 11, 2017, 06:42:46 AM Hi,
I'm new here, but I've been given an EII+ HD to fix for a friend (I know my way around electronics so don't worry). It's been sat in a garage (dry) for 20+ years and when he powered it up it lit up, then after a short while went "pop". My suspicion is that after 20+ years of sitting still the PSU caps have dried up and are kaput. SO I'd like to start with replacing it. One thing of interest to me is the output ratings, I understand from reading this thread that there is +5, +13.2 and -12. the +13.2 is a little odd, but hey this was the 80s. But does anyone know the current limit for each of the rails? Sure I could put in an 80W PSU, but if it only needs 40 then it's a tad overkill. For those interested in getting a +13.2 from a +15 rail, you could use a variable regulator (for example an LM317T) but again it depends on the current draw. I suspect that with the HDD that's installed on this unit (which is probably dead) it'll pull more than the regular PSU. This is the PSU I'm considering - https://www.digikey.com/product-detail/en/tdk-lambda-americas-inc/CUT755FF-B/CUT755FF-B-ND/5180377 The LM317T is limited to 1.5A, which is my primary concern as the HDD+FDD may pull more than 1.5A Any advice would be very much appreciated. Thanks Paula Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: alka on June 13, 2017, 10:56:55 AM Can't speak to the amperage and current needed but I thought it was mentioned earlier in this thread. I believe you will need at least a 60 Watt PSU. As for anyone concerned with getting the +15V rail down to around +13.4V, three 3A diodes in series in between the Mean Well T-65C (or similar) +15V connection and the +13.4V wires works great.
Apparently the analog electronics are doing fine with the +15V rail but I would especially be concerned with the models that do not have the special +12V line to power the 5.25" floppy drives. Running those at +15V is risky so I hear, as appears to be the case with This is Not America's image above. Title: Re: Emulator II: Supply Rails and PSU Harness Colour Codes Post by: Paula on June 17, 2017, 10:14:28 AM alka,
Thanks, The SSM2045s will be fine with +/-15V, as you say a few diodes would solve the problem. Just check my PSU, 240V ac going in on J102, nothing coming out. Onboard fuse intact so it's time to go read schematics (I loathe switchmode PSUs) Paula |