Emulator II: Supply Rails and PSU Harness Colour Codes

[ahaigh01]

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.

[ahaigh01]

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.

[moellhoven]

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.

[ahaigh01]

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..

[moellhoven]

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

[Gregory]

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

[moellhoven]

Thanks Gregory. Will be patient for a couple of days until the floppy emulator is installed.

[Electro disco club]

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

[moellhoven]

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!

[Elmbeatz]

....

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

Greetz,
Elm.

[moellhoven]

Brilliant

Thank you for letting me know.
Will try this out on the weekend!

cheers,
André

[Gregory]

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.

[Electro disco club]

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

[Paula]

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

[alka]

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.