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Exidy Sorcerer II Questions

tempest

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Joined
Sep 16, 2014
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SE Michigan
I just bought a functioning but 'in need of repair' Sorcerer II from Chromedome45. I'm excited because I've wanted a Sorcerer for years, but before I can really play around with it I need to fix its issues.

1. The main problem with the unit is that the video output has some sort of distortion, like a constant waviness to it (it actually almost pulses). I'm thinking that the issue is probably related to some bad caps either in the power supply or on the main board itself. Has anyone seen something like this?

2. The second and less serious problem is bad RAM. The Sorcerer is reporting that the top of the stack is FFFF which obviously isn't correct since the Sorcerer only supports 48K RAM. I'm guessing the cause of this is either bad RAM (most likely) or the dip switches on the motherboard are set wrong (less likely). Right now they're set to 0111 which according to the tech manual means:

Switch 1: On - 50hz / Off - 60hz
Switch 2: On - 3 rows of RAM (which is what I have) / Off - 2 rows of RAM
Switch 3: On - 16K RAMs (which is what I have) / Off 4K RAMs
Switch 4: On - 2 rows of RAM / Off 1 row of RAM

I assume that if you have 3 rows of RAM (switch 2 on) that switch 4 is ignored. Otherwise nothing would make sense. The Sorcerer has some sort of memory test built in, but I'm not sure how to use it.


3. Not a problem, but I'd like to upgrade the Sorcerer monitor to version 1.1. To do that I need to replace the monitor ROMs with some burned EPROMs. What kind of EPROMs does the Sorcerer monitor use? I assume they're standard 2716's, but are they 3v or 5v?

I also saw a blurb in a Sorcerer newsletter (July 1985) about an error in the tech manual when replacing the monitor ROMs, but I don't have access to the August 1985 letter where the fix is actually discussed. Anyone know what the 'fix' was? If I plan on swapping in EPROMs with the updated 1.1 monitor, this info would come in handy!

In the next newslatter I will have a replacement diagram for the error in the Sorcerer II Technical Manual dealing with conversion of the main board from Monitor ROM's to standard 2716 EPROM's. It's easy.


Any help would be greatly appreciated. Also you can read Chromedome45's attempts at repairing the unit before he sold it to me here: http://www.vintage-computer.com/vcf...ce-check-what-would-you-pay-Exidy-Sorcerer-II
 
I'm sure that the waving is due some bad caps in the power supply. Most if not all of the caps in the sorcerer pcb itself are tantalum ones; so they're more reliable...
The switches are correct for a NTSC machine, as I stated in the other thread, mine are all in ON position. With three rows of 4116 ICs it must work. Of course you can always test it with only one row; but I'm not really sure of what row is used in this case.
I'll need also to test all of this as I found that my own Sorcerer seems to have died silently after some months of inactivity :p

About the roms, IIRC mine has a PCB with EPROM mounted instead mask roms, need to recheck this.

Right now I'm in the process of moving home and I have a big mess with my collection
 
I'm sure that the waving is due some bad caps in the power supply. Most if not all of the caps in the sorcerer pcb itself are tantalum ones; so they're more reliable...
That's good to know. Chromedome said he replaced the power supply caps, but maybe he missed some or got a value wrong (I think he said he changed one because it had the wrong value installed). I'll have to see. Now that I have the Sorcerer II tech manual (thanks to Snuci)

Of course you can always test it with only one row; but I'm not really sure of what row is used in this case.
I believe it's row 3. It's in the tech manual anyway. I believe Chromedome said that he added RAM to rows 1 and 3 and the original RAM is in row 2. My plan is to remove the added RAM and make sure the system loads with the original 16K. After that I'll try adding a second row and see if it comes up with 32K. Then I can swap in the remaining chips one by one and see which one is bad. If I can't get anything above the original 16K working then the chips Chromedome used may be the wrong kind or value. I'm not worried about the RAM so much as that should be easy to diagnose.


About the roms, IIRC mine has a PCB with EPROM mounted instead mask roms, need to recheck this.

I'm pretty sure the monitor EPROM replacements are just 2716's. I'm going to have a friend burn a copy of the 1.1 monitor for me and just try swapping them in. If they don't work then I'll need to look into it closer. The quote from the Sorcerer newsletter still worries me though. It seems to indicate that it's not just a drop in replacement.
 
I also think that slowly increasing the amount of RAM is the right approach, let me know if you find the working single row!.
If all the PSU caps has been changed, it's time to find noise in the voltage lines and/or video signal with an oscilloscope, if they're clean it must be a synch issue (maybe there're pots in the PCB used to regulate this, can't remember). If the voltages have noise even after the caps replacement you'll need to trace each line looking for aging components (regulators?), need to check that schematics right now! :p
 
We figured it out. The issue was twofold: a bad cap on the 12v line and the dip switches were set incorrectly. Apparently the Sorcerer II tech manual is wrong and the text on the motherboard is correct. The video issue was most likely due to the sorcerer using the video memory for regular memory because it couldn't detect any of the installed memory.

Now I need to figure out how to get programs to the Sorcerer. Any tips on making tapes from mp4 and wav files? Are all the various Sorcerer games available somewhere?

BTW is it normal for the Sorcerer to run really hot? I just ran the 48K memory test (it passed) but the back of the system is really warm. It also has that 'warm electronics' smell if you know what I mean. Not a burning plastic smell or anything, but a warm components smell.
 
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The main fix was replacing the blue cap next to the second row of memory so the 12V line wasn't shorted. The writing on the motherboard is actually correct for the dip switches. I'll have to check when I get home what they're set to. I wonder why the tech manual was completely wrong? For example, switch 1 has nothing to do with selecting between 50Hz and 60Hz.

I'm having a hard time making game tapes. My main problem is that MESS is now part of MAME and the settings mentioned in this article (http://www.classic-computers.org.nz/blog/2011-06-18-sorcerer-software-stockup.htm) are different. I'm also having problems finding software and when I do it's in all kinds of different formats (.bin, .wav, .snp, .rom, etc.). Does anyone just have .wav files I can transfer to tapes?
 
FWIW, you might want to read Mike Brutman's experiences with working with waveforms. Good discussion here that kind of parallel's that which you've already read about on Tezza's site. Click.

Afraid that I'm not familiar with software for the system though. I am quite glad that the unit found a good home, however. I was digging with Chromedome45 when we found that little box... my eyes got big when I saw the "E" on the Exidy box, as I knew it was going to be a good find!
 
Ah Mike. I know him from his PCjr forum. I'm sure he could help.

So where did the unit come from? I didn't hear the tale of its discovery.
 
Good to know you fixed the Sorcerer!
I'm also eager to know your findings about the dipswitch use. I was sure that switch 1 controlled the 50Hz/60Hz mode...

Sometime ago I succeeded in generating WAVs for my Sorcerer using MESS. Basically the tricks were using the correct MESS version (can't remember right now; but newer versions were bad, only an old version worked fine for me in generating a WAV that loads) and creating WAVs with lower baud rates. In the monitor you need to lower also the baud rate.

Thanks to Tezza I was able to load from tape a TRS-80 BASIC. I modified that BASIC to correctly support the graphics mode of the Sorcerer :)
 
Anything you remember about making Sorcerer tapes would be great. I assume that things have changed enough since the merger into MAME that the old tricks for making tapes won't work. I might be wrong on that, but I can't get anything working on MAME at the moment anyway. Do you still have your WAV files? What monitor commands did you use to lower the baud rate?

I'll look into the dipswitch settings tonight (I completely forgot yesterday), but if you look at your motherboard the writing on it is correct. IIRC I have three dip switches ON and one OFF (the one that selects between 4K and 16K). I want to say it was 1,3,4 On or possibly 1,2,4 ON.

We tested Dipswitch 1 with my monitor. There was no difference between the positions. I was using an NTSC 1702 monitor which should have moved the image when displaying PAL (or possibly started rolling), but there was no change in the display whatsoever.
 
What a mess, so seems there's no switch for selecting 50hz/60hz?

I'll try to refresh my knowledge about generating WAVs ASAP. Indeed I still keep the WAVs, IIRC they're even stored in the PDA used to play them.

As for the 300 baud mode, type "SE T=1" in the monitor to change, use T=0 to set back the original 1200 baud (extremely unreliable in my Sorcerer).
 
Well when I had it it looked like you needed to cut some traces and add some jumper wires to enable 50Hz mode. It is painted on the mainboard on which traces to cut. But I didn't bother to mess with it.

Ok as to how it was found:

Maverick1978 and myself have a friend who owns a warehouse full of odds and ends including some vintage computers typical IBM PC's A couple of PCjr's Amiga 500, commodore 128D and the like. Well Maverick1978 was digging around a pile of boxes and he saw that one had a big "E" on it as he had mentioned. He pulled it out and it said "Exidy Sorcerer" on the box.

We both got really excited about the box and opened it up and there she was. In really good cosmetic shape as you know.

So I asked the owner to let me mess with it and he said ok.

When I opened it up the one power supply cap looked like it was ready to explode. So I replaced it with a like value. Then looking at the schematics turns out that the Cap in question was the wrong value. So I put in one with a higher value then was called for.

As for the small blue tantalum caps around the memory chips I could have swore I checked them all with an ohm meter. Well maybe I missed couple. So my bad on that part. But at least it's working right now so great job.

And well you know the rest of the story. So that is how we found it. The owner didn't even know it was there.

As for the RAM chips I used they were all 16k just different manufacturers with odd part numbers like the Fujitsu 8116's etc and some MOSTEKS which were the original chips that were in there.

So good luck with it @Tempest
 
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I know on the Model 1 Sorcerer you need to cut a trace to get 50Hz as Chromedome said. A while back I was going to get a PAL Sorcerer and try and convert it to NTSC so I looked into this. Here's what I found in an old newsgroup post:

> The original Sorcerer manual has a page explicitly devoted to 110/60 to
> 220/50 modifications. Mods are required for both the PS and the video
> circuits. If there is a similar page for the II, that would be really
> useful (as Thomas the Tank Engine says).

The 110V / 220V mod is all you need to take care of the power; the
50/60Hz mods are purely for the video. Actually I (and many others)
found the modification for 50Hz wasn't bad on a Mk.II but rather less
than perfect on a Mk.I, and there are some variations.

The Master Timing is the one you'd want in order to understand the
50/60Hz change. Logically, the Power Schematic would be the one for
110V/220V, but it doesn't actually show the transformer primary.

On a Mark II, the 50/60Hz is set by one section of a DIP switch at
location 11A. Section 1 of that is on for 50HZ and off for 60Hz. When
on, it grounds the /SEL inputs on a pair of LS157 muxes which are part
of the feedback in a set of counters made from a couple of LS161s and an
LS74.

The other parts of that switch control whether you have 3 rows of DRAM
(on) or 2 (off), 16Kx1 RAMs or 4Kx1, and 2 rows or 1 row.

From the manual:
"For 110V, the power supply transformer primary windings are
connected in parallel; to convert to 220V, disconnect them and
wire in series. Do this by cutting the black-yellow and black-red
wires at the line filter, and soldering them together."

On mine, they're neatly soldered together inside some sleeving.

If you look carefully at the line filter mounted to the left of the
transformer, you'll see that one terminal has a black-green wire going
to the transformer, and that's the one that the black-red wire should
connect to for 110V. The other terminal has a plain black wire, and
that's where the black-yellow wire should connect for 110V.

I'm not sure if he was just getting the same wrong info out of the tech manual or he actually verified it himself. When we tried setting the switches according to the manual they were wrong. I think with 2,3,4 set to ON (what the manual says would be the correct config for a NTSC 48K system) we were getting only 4K or 16K. I have a hard time believing that you can turn a PAL Sorcerer NTSC or vice versa with the flip of a switch, but if someone can verify this I'd appreciate it. I think my PVM monitor said that it was generating a 60Hz signal with 1 set to ON, so that would prove the manual is wrong. I'll double check this weekend.
 
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Quick question for everyone. Is it normal for the Sorcerer video output to have a little 'interference' to it? I noticed that the image is pretty solid, but it still has a tiny little bit of 'ripple' or 'interference' to it now and then, especially when there's calculations going on (like during the memory test). It's nothing major, but it's there if you look for it.
 
Honestly, I can't remember, indeed the Sorcerer's video output was very solid; but maybe yours have some weak caps and the video signal is a bit noisy...
 
Quick question for everyone. Is it normal for the Sorcerer video output to have a little 'interference' to it? I noticed that the image is pretty solid, but it still has a tiny little bit of 'ripple' or 'interference' to it now and then, especially when there's calculations going on (like during the memory test). It's nothing major, but it's there if you look for it.

Yes it's normally solid. From memory I think mine has a very slight barely noticeable ripple, which I put down to old caps.

Tez
 
Yes it's normally solid. From memory I think mine has a very slight barely noticeable ripple, which I put down to old caps.
Tez
Yeah that's what I'm talking about. It's 'just' noticeable, but gets worse as things gets busy. I'm curious as to what it will look like when I get something full screen running on it like a game.
 
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I'm the one who helped tempest find and replace the shorted cap. I also have a Sorcerer 1 board (no case and keyboard) which I modified in the day for 56K DRAM and 3rd party keyboard. I'll try to get it working again so we can see about the ripple.
 
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