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Emax Plus SCSI Retro Instructions – PDF


2nd Emax II

Well, since the first Emax II had no memory expansion or Stereo upgrade I began the quest for another unit.
I found one via Craigslist.
Took the boards and put them in my recently repainted unit.

So I now have a 8MB Stereo Emax II! Yahoo!

My next item of interest was to see if I could re-create the Emax II Stereo update.
I attempted to duplicate the PAL and determine the stereo setting bit(s) in the 93C06 EEPROM.
But that didn’t work out.
Then I tried taking a copy of a previously stereo unit and use that EEPROM binary to replace the original EEPROM.
That didn’t work either.
So no dice on that update- I won’t be able to make it.

So now, I will sell the logic and audio output board from that unit if someone wants them to hopefully recoup some of my costs….

Emax II – The Restoration

So I received the Emax II and it definitely needed some work.
The case was somewhat scratched up.
There were 6 broken keys and 3 with gouges in them.
It didn’t power up.

So I first had to work out the power problem.
One pole of the two pole power switch was bad – bypassed for testing….
Power On- floppy appears to have some issues, will replace with the slim floppy and a PC Card drive anyways- so no big worry there….
Dim Display- but workable…

No stereo- was hoping it had this update.
1MB memory- so no expansion- just no luck here with any of the upgrades…

Try the keys- not responding very well, they have to be pounded to get any sound.
Close inspection reveals that the unit got liquid all up in it, it’s a mess.
The key contacts are all gummed up.

Spend 3+ hours cleaning the contacts with rubbing alcohol, Q-tips, and a dental pick.
Keys respond OK now.
There is mold in the case all over- most likely growing on the remains of the liquid that was spilled in here….

Hit up Ebay and buy some replacement Emax white keys.
Hit up and order-
new power switch
capacitors to re-cap power supply
capacitors to re-cap audio signal board of Emax 2 and Emax 1.
EEPROMs so I can do testing as to Stereo and Memory upgrade research in the future.
Got a part for the Stereo kit, in the event I recreate that.
The Crystal CS5326 / 5328 is going to be the hard part to get if I need it….
Find out Route 66 Studios may already be able to re-create the Stereo update- waiting to hear back from him in two weeks or so….
Hit up eBay again- I am gonna have two working keyboards- I need a keyboard stand with 2 tiers…

Remove everything from the case, scrub with Vinegar and a nylon brush to get rid of the mold and also to clean / prep for paint.
Mask the case up, covering the logos, input /output info, etc.
Repaint, then clear coat.

A week goes by during the paint / clearcoat process and I get the keys replaced in the keybed, the PS and Audio board re-caps done….
I cut and drill the mounting brackets for slim floppy to mount onto the PC Card drive.
Mount it up.
Put the stock parts back together- getting so close to being done.
Somewhere in all of this, my replacement slim floppy is flaky- gotta hit eBay again for a replacement….
The backlight on the display also went out. Will anything go right?
Fortunately for me, when I bought the Emax 1, I ordered displays in advance – 2 of them.
I replaced

the Emax 1 display right after I bought it.
So I have a display for Emax 2 already- pop it in- no words!!!
Hit up Jammie in the UK and he gives me the answer- the reflective angle is wrong.
Cut trace to pin 3, add 20K pot and VOILA! We have words on the display.

THANKS and a shout out to Jammie!

So now- waiting on Slim Floppy drives from eBay, possible Stereo upgrade.
The keyboard stand arrives today.

I will post some photos of before and after…. and also the Emaxes with PC card drives installed (Emax 1 and 2 keyboard and Emax 1 Rack.

Emax II

Went on ebay today and got one, finally.

It is in “AS IS” condition, so needs repair. But once that is done, I will have one for using as well as testing.

Unless the echip is dead, I should be able to fix it.
Then if someone asks me a question about Emax 2 at least I can answer it!


All the PC Card drives and Zip drives with SCSI bridges have sold.
I only have SCSI update kits without drives available at this time.

*** I seem to be getting a few queries as to when I will get more drives. The answer is Рmost likely never. I just happened to find a batch of  USED read-only drives on eBay. I was able (after 2 or 3 weeks of searching google and contacting several companies) to acquire firmware to make them read/write and this enabled me to make them usable for general use. Unless I am lucky enough to find another batch of drives like that, I believe this was a one time opportunity.

You can however still get these drives NEW from here:
Only 1 slot in the PCD-50b works in Emax (the PC Card slot) due to these being LUN based units.
I cannot confirm any compatibility with Emax 1 or 2 in regards to the PCD-60b.

If someone has a PCD-60b that didn’t work for them in an Emax I would be willing to test it out / see if I can make it work in Emax 1 or 2.

Drive power readings

I have an Acard 7720U SCSI to IDE bridge. This works fairly well.
The 7220U works with Zip and IDE PC Card drives in Emax without additional adapters.
I found 4 x  Acard 7722 SCSI to IDE bridges denoted as working with ATAPI devices only.
IDE Zips are listed as ATAPI in their part number.
I did some testing, and the 7722 bridge will work with the IDE-ATAPI Zip drives in a PC or the Emax.
I tested with a Zip 100 and a Zip 250.
Caveat- The bridge firmware must be updated to:
1.77a for ver 1.6 PCB
1.77b for ver 3.0 PCB (RoHS compliant)
This requires a PC with a SCSI card. I used an Adaptec 2940U2W with firmware v3.10.0.
The SCSIDE bridge boards are LVD and therefore, do not have the 50-pin connector as is present on Emax.
They must be "adapted" to the correct connector.
They do successfully boot the Emax.

Slim Floppy Drive testing.

Just an update- I have gotten  a couple of different slim floppy drive brands now, and they worked fine with the Floppy Converter.
I have now tried:
TEAC Model: FD05HG
Sony Model: MPF820
NEC Model- FD1238T
All worked.
I am beginning to think most slim floppy drives should work.
If the wrong flat cable is used with a floppy converter there will either be no activity / lights or
what will be exhibited is two red lights on the Panel when running diagnostics, much like if you have no floppy or bad floppy hooked up.

If your floppy drive comes with a cable, and you have a cable which came with the converter and are confused which to use,  you should always use the one that came with the floppy converter.

Additional update-  The converters are no longer available for sale.

If you purchase a JM-215A I can provide modification instructions.

I may just post the instructions and a picture here…..

I have now gotten a used  PACE desoldering station, fixed it, and am willing to modify REV 2 boards for those who are uncomfortable with performing the ugprade themselves.

Cost is $100 USD + shipping.

To clarify: $50 for the kit, and $50 for installation labor.
It includes installation and verification the modification is working prior to return shipping.

Removing the Socket

Removing the socket is the reason for purchasing the Desoldering tools and also plays into getting the good soldering iron, as replacing the socket is the biggest (read hardest) part of the upgrade.

I removed a socket recently to brush up on technique, but don’t have more to show as an example, or to make a video of.

I can give you these tips, though:
1) Add a little solder to every pin of the socket before you begin your removal process.
Adding the solder can make it easier to remove all the solder, whereas just heating the existing solder and then trying to remove it will fail many times. Factory solder (especially when wave solder machines have been used), often need this technique applied for successful part removal.

2) Cut the rails that interconnect the two lines of pins.
I just used small diagonal cutters to snip through the plastic which worked fine.
The thing that makes the socket difficult to remove is that there are so many pins.
Getting them all unsoldered at the same time can be difficult. Which brings us to….

3) Once you have broken the rails, carefully cut the socket apart with your Xacto (or similar) knife.
You may also be able to use small diagonal cutters (I did). But this comes back to being GENTLE with stuff.
Be careful with it. Take your time. Be careful not to damage the traces below the socket that may come out between the pins.
I cut between every two or three pins.

In this way you are really only having to desolder 2 or 3 pins at a time to remove the section of socket.

4) If you are having difficulty desoldering a particular pin or section, move on to a different section.
This allows that area of the board to cool down from failed attempts, and should also help if you are getting frustrated.
Later, when you only have one or two sections left to remove, you won’t feel as if you have not made any progress.

5) When desoldering each pin, make sure it is not stuck to the "wall" of the pin hole. You can do this by GENTLY rocking the little section of socket back and forth after you have removed the solder from the pin hole. If you heat a pin that is stuck to the side and rock it away from the wall and hold the socket with the pin away from the wall then it will cool and be free. If you rock the socket back and forth now you should see the pin move.

So for example lets say you have 3 pins, two are free and one is not. You should be able to heat that remaining pin and while it is hot, pull the section of socket away on the other side.
You may be left with a hole full of solder, but this should be easily removed since the pin is gone. It may be necessary to remove the solder from the top or the bottom. Additionally you may need to add more solder to the hole.

If an attempt to desolder a pin hole fails, add more solder back in. If solder is basically stuck on the opposite side of the board, adding more solder will usually allow it all to flow together for a successful second or third try at removal.

That is about all the tips I can think of for today….

Happy modding!