Jump to content


Hi-Res Bally Arcade/Astrocade Correspondence

1 reply to this topic

#1 ballyalley OFFLINE  



  • 1,372 posts
  • Location:Albuquerque, NM

Posted Thu Jul 7, 2016 2:30 PM

I have added correspondence from 1985 and 1986 between Michael Matte, Don Gladden (who edited volume 6 of the Arcadian) and Bob Fabris.  Michael wrote the documentation on how to upgrade the Bally Arcade to hi-res mode.  His letters primarily deal with this matter, but he also drops some wonderful tid-bits, such as that he made a BalCheck II for his hi-res unit.  He also upgraded the Machine Language Manager cartridge so that it could take advantage of hi-res mode.


Michael's Astrocade High-Resolution Upgrade documentation is available here:




I have added the correspondence to this upgrade area.  I've also revamped the entire area.  I added details about what is in the documentation "packages" that Michael wrote (I'll explain that in more detail in another post that I'll make soon).


Some of the letters were typed and some were handwritten by the authors.  I have used a combination of retyping, OCR and voice-to-text (using Dragon) to make the letters into text files (and searchable pdfs, in the case of the typed letters).  Rather than linking to the letters, I'm going going to include them in-full here:


1) Letter to Don Gladden from Michael Matte (June 7 and 8, 1985)


June 7, 1985


Dear Don:

I personally would like to have the option of programming on a high resolution screen. I have interfaced Texas Instrument's TMS9918A video display processor with my Astrocade computer, the chip having a high resolution mode, but I would prefer to program on a high resolution screen mapped by Bally's custom address and data chips because Bally's high resolution map (320 x 204 pixels) is easier to work with. Recently I have attempted to get my Astrocade computer to operate in the high resolution mode. I was aware that Datamax Inc. manufactured the Datamax UV-1 computer (16K ROM, 16K Screen RAM, and 32K User RAM) which utilized Bally's 3 custom address, data and I/O chips. In July of 1984, per my request, Datamax sent me copies, for a price, of electronic schematics and PC board layouts, but to my surprise, the copies were for their upgraded UV-1R (32K ROM, 256 Multipage Screen RAM, and 32K User RAM) computer.

With the aid of these schematics I came up with a scheme allowing my Astrocade computer to operate in the low or high resolution mode. Unfortunately, there's a "bug" in my scheme. I can display the high resolution map, write to it or read from it, and perform all the magic functions on it, but I get these glitches on the screen, occasionally, which appear and disappear. I used 0.1uf bypass capacitors judiciously for the four 16k banks of Screen RAM (I used type MK4116N-4 chips) and all other chips. I think the problem is somewhere in the timing.

Datamax's CPU board layout, where the Bally custom address and data chips are located, doesn't quite agree with its CPU board schematic, i.e., some resistors and capacitors appear on the CPU board layout but NOT on the CPU schematic. Datamax's scheme for the microcycler is almost identical to Bally/Astrocade's microcycler. Datamax added a chip to their microcycler which doesn't look like it's wired correctly (a drafting error?) and I haven't been able to figure out the reason for that additional chip due to lack of appropriate information on the Bally custom address and data chips. True, the Dave Nutting Associates manual provides information on the 3 custom chips, but offers no help as to how one would wire the required four 4K banks of screen RAM (and microcycler?) to get the high resolution map. What I would like to do is get my hands on copies of Datamax's UV-1 computer back in 1981 when it was a simpler system having only 16K ROM, 16K Screen RAM, and 32K User RAM.

I said all of this hoping the Arcadian might be able to help me out. How many other Bally/Astrocade computer users would be interested in expanding their system to provide an optional Bally high resolution map? Could you possibly print the following ad in the Arcadian? [I couldn't find the ad that Michael refers to to in the Fabris Collection, unless Michael is referring to the entire second part of his letter, dated the next day.]


June 8, 1985

Dear Don:

I would like to provide for each new issue of the Arcadian an article on machine language programming for the Bally/ Astrocade computer. Hopefully the article would generate interest in some users to explore this powerful language. Perhaps programs with complex graphics might be created as a result of this interest.

With regard to submitting my articles to you, I have no idea as to how the Arcadian produces some of its articles with such small print. The only printer I have is an electrical typewriter. I could submit my articles to you using a double column on a 7" x 9.5" space giving you room for a border line, the Arcadian logo and so on. Would I be allowed to fill 3 pages (sides)? I have a lot of information to share, information that I haven't seen in the Arcadian (Vol. 4-6). Please give me some input regarding article submittals.

I realize you don't know what my background in machine language programming is. My articles will stress examples. Let my examples establish my credibility. I can show how to create fast non-blinking graphics.

This paragraph is for the Arcadian's information (for whatever its worth) that we users might pool our resources and continue support of the Bally/Astrocade computer. I haven't submitted any written material to the Arcadian previously because I have been working on projects for use with my Astrocade computer, projects such as:

1. A substitution for the Bally/Astrocade AC power transformer

2. Adding (or replacing RF modulator with) a composite video output and audio output for improved picture and sound

3. Interfacing Texas Instrument's TMS9918A video display processor

4. Adding 32K dynamic RAM addressed 8000-FFFFH and

5. Adding switchable 12K static RAM addressed 5000-7FFFH along with a video-cade copier connector.

I plan to build an eprom programmer that can be used with the Bally/Astrocade computer so that 2K, 4K and 8K EPROMS can be "burned", I also plan to develop a troubleshooting procedure and troubleshooting/check program for a Bally/Astrocade motherboard and hopefully any memory add-on. Incidentally, substitutions or equivalent replacements for any electrical/electronic component in the Bally/Astrocade computer will continue to be easily available, with the exception of the 3 custom chips and perhaps the +10V voltage regulator LM342P-10 (component #VR2). Most probably, the 3 custom chips will eventually be unavailable. The +10V voltage regulator is not used often and may eventually be unavailable. Jameco Electronics (415-592-8097), for example, is clearing out their stock of the IM342P-10 (it is listed in their flyer #127). For those who have committed themselves to the use of their Bally/Astrocade computer (I know I have), my advice is to take advantage of ABC Hobbycraft's sale on Astrocade units for $34.95 and motherboards for $5.00 so you have some back up parts while they are still cheap and available.

Michael C. Matte

2) Letter to Bob Fabris By Michael Matte (December 21, 1985)

Dear Robert:

Thanks for responding to my 8 June and 7 June letters sent to Don Gladden, whom I have not received a response from.

I have a lot of information that I would like to share with the ARCADIAN. However, I question some of the information that I have as to whether or not you can publish it due to possible infringements on copyrights or perhaps patents. What I will do is send my own creations (tutorials, upgrades, whatever) to Don Gladden and to you I will send any questionable material indicating the source(s) of info for you to do with as you desire. It is my desire that support of the Astrocade home computer will continue.

Right now I have doubts that the ARCADIAN will continue publishing issues. Upon receipt of the next issue (Dec. ’85?), I will send an article to Don detailing a power transformer substitution for the Astrocade computer. After receipt of each future issue of the ARCADIAN, I will send to Don a tutorial on programming the Astrocade computer in machine language. I have already written several tutorials on this subject just waiting to be submitted to the ARCADIAN. Further material on other subjects will be sent to Don or yourself, of course at my discretion.

You asked me if I was aware of the Balchek program. Did you know that there exists a Balchek II? Yes, there is! Balchek II is an improved version of Balchek enabling its user to also check a RAM add-on. I have gone through the disassembled listing of Balcheck, have made some changes and deleted some of the useless routines to allow room to check a RAM add-on. Yes, Balchek II does exist, although not quite finished yet. I have a copy of it on tape. Wish you could see it.

There is something else I wish you could see. That is, the Astrocade home computer running with a high resolution map (320x204 pixels). What a difference! I have resolved the high resolution glitch problem described in my June '85 letter I sent to Don. I am currently writing an 8K byte software package to be eventually burned on an EPROM. The package will contain an improved 2K byte high resolution version of Bit Fiddler’s MLM, 2K bytes for 33 high resolution subroutines (similar to the onboard subroutines) and 4K bytes devoted to extended high resolution graphic subroutines. My Astrocade computer can now operate with a low or high resolution map. Unfortunately, modifications were required on the motherboard to get the on-board custom address and data chips to operate in the high resolution mode. I can't see any way of getting the on-board custom chips to operate in high resolution without making some modifications to the motherboard. You mentioned John Perkin's efforts.

What did he do? Perhaps a second set of custom chips and associated circuitry could be utilized as an add-on, but where would one get the custom chips from? Or perhaps the circuitry could be provided as an add-on and then the 3 on-board chips removed from their sockets and placed in their respective add-on sockets? It would be nice to come up with a simple means of providing any Astrocade user, how few there may be, the option of high resolution graphics, but it doesn't look like that's going to happen. Any comments?

Michael C. Matte

3) Letter to Michael Matte by Bob Fabris (December 26, 1985) - Draft

12/26 [1985]

Dear Michael [Matte],

Your most interesting letter just arrived and I thought I'd best get back right away.  Primarily because there is no point in sending anything to Don Gladden.  He's not involved with Arcadian production any longer.

We'll certainly keep the Arcadian going for two more issues (I trust you received the December issue by now).  Whether to go after issues 3 and 4 depends on reader response and material to print.  It does seem like we have a somewhat dedicated kernel of Arcadian enthusiasts.

Balcheck II?  Now that's a big surprise!  Is Dick Belton aware of your efforts?  I'm sure he would find it very interesting.

And a high-rise machine too!  Motherboard changes are acceptable-- I recall John's board had lots of piggyback memory attached-- I'll try to get in touch with him-- I think he is still with?  We have some motherboards here and some spare chips as well.  Actually, the units themselves are getting so cheap that one can build up the extra parts relatively cheaply.

[Bob Fabris]
4) Hi-Res Package Cover Letter (to Bob Fabris) by Michael Matte (July 3, 1986)

July 3, 1986

Dear Robert:

Enclosed are five, what I have labeled as, "packages" for use as you desire.

I've thought about the possibility of production or sales for package 1 upgrade.  It would be great to play with games utilizing high-resolution graphics.  However, I see many complications.  I would be willing to make the necessary modifications to any motherboard and perhaps wire the power supply, but I have really little desire to wire wrap anymore RAM boards or audio/video boards.  Who would have the skills to layout and manufacturer a PC RAM board PC audio/video board?  Since much of the video RAM and composite video electronics was taken from the Datamax UV-1R computer, wouldn't permission be required from Datamax to market the RAM board and audio/video board?

What common means should be used to program the Astrocade high-resolution graphics: ZGRASS and/or a machine/assembly language monitor or BASIC?  I can't see how I could market any Hi-Res MLM [Machine Language Manager cartridge] if it utilizes portions of Bit Fiddlers' MLM, an Astrocade BASIC PC board, Astrocade BASIC routines for the audio interface (>=8000H constraint deleted) and routines almost identical to the Astrocade onboard subroutines?  DataMax utilized, at one time, 16K bytes ROM (including ZGRASS) for their UV-1 computer.  Perhaps this could be utilized into the upgrade.  However, the DataMax UV-1 computer required the use of a computer terminal.

What common means of saving data should be used?  Would an external keyboard be required?  Obviously, to get the most out of the high-resolution graphics, a common means of programming in that mode is required.  A group effort is indeed required to get the job done and maybe some input from potential users.  So tell me, is there a next step?  I need help on this one.  Who has the desire to invest in such a project?  Would there be enough interest to make the project feasible?

Recently, I read a Viper sales brochure claiming that their 8K/24K switch allowed any cartridges in the cassette slot to be copied out to Viper RAM.  This puzzled me.  Do you have any idea how this copy feature was accomplished?  I can see how the Z80 could read data from a cartridge and by electronic trickery, the same data would be written to RAM.  But this would require the user to utilize every aspect of the cartridge, so every byte of the cartridge would be read by the Z80. The 8K/24K switch in packages 1, 4 and 5 only allows the user to develop software addressed 2000-3FFFH with the intent that the software would eventually be realized in cartridge form.  That is, machine code can be entered/loaded into 6000-7FFFH and then switched to the respective locations in 2000-3FFFH.

Please explain your reference to Dick Belton, i.e. is he troubleshooting RAM add-ons?  What's his address?

As usual, please mail the enclosed postcard, so I know you received the enclosed material.

Michael C. Matte

P.S. In case you're wondering, I spent much time developing the upgrade and Hi-Res MLM for my own use.  I also had the hope that more experienced people might take the upgrade and somehow market it and that I might act as an advisor or maybe even a partner.


The hi-res Astrocade upgrade is very intriguing to me, and I figured who wouldn't want to read more about it from these letters.  Does this get anyone interested in upgrading their systems?



#2 ballyalley OFFLINE  



  • Topic Starter
  • 1,372 posts
  • Location:Albuquerque, NM

Posted Thu Jul 7, 2016 2:43 PM

I have added details about the documentation that Michael Matte wrote about each part of his five "packages" in today's revamp of the Astrocade High-Resolution Upgrade area on BallyAlley.com.  Michael's documentation is handwritten, so I re-typed and used Dragon voice-to-text to create the descriptions, which (in most cases) are just slightly edited quotes of Michael's own descriptions of his "packages."

Hi-Res Package 1 - Astrocade System Upgrade

"Package 1" of the Astrocade System Upgrade (low or high resolution graphics, user RAM, composite color video output and audio output) contains fifteen pages of schematics and layouts. Here is what is included in Astrocade Hi-Res Package 1:
  1. Contents
  2. Modified Motherboard Schematic
  3. Modified Motherboard Layout
  4. Power Supply Schematic/Regulator Board Layout
  5. Ram Board 50-Pin Contact Expand Interface Schematic
  6. Ram Board User Ram Decoder Schematic
  7. Ram Board User Ram Schematic
  8. Ram Board Video Ram Interface Schematics (Two)
  9. Ram Board Video Ram Schematic
  10. Ram Board Layout
  11. Ram Board Optional 16K Rom Decoder Schematic
  12. Ram Board Spares
  13. Audio/Video Board Schematic
  14. Audio/Video Board Layout
Drawing Comments
  1. RAM Board Video RAM Schematic - Type 4116 dynamic RAM is used in lieu of type 4027, since it is generally cheaper and easier to obtain.
  2. Ram Board Layout - Close To Actual Size
  3. Ram Board Optional 16K Rom Decoder Schematic - Scheme Is Untested
  4. Audio/Video Board Layout - Type LM377 audio amplifier chip is probably discontinued. Other audio amplifiers can be substituted. Radio Shack, for example, has several audio amplifier chips.
  5. Audio/Video Board Layout - Close To Actual Size

Hi-Res Package 2 - Low/High Resolution Modification Procedure

Nineteen pages describing what and how to modify the Astrocade motherboard, plus how to wire the RAM board, which contains video and user RAM.

It is assumed the user of this procedure has a copy of the Bally Service Manual PA-1. Beginning experimenters in digital electronics should not attempt this upgrade. Several unused gate inputs are shown wired to +5V via a 10K current limiting resistor allowing TTL chips to be occasionally substituted in lieu of LS TTL chips. If only LS TTL chips will be utilized, then wire the unused inputs directly to +5V (no resistor). Numbers following procedure statements indicate reference should be made to the note numbers, which are listed following the procedure.

Two low resolution demos and a high resolution demo, for testing purposes, are available on cassette tape. Mail the request for the demos along with $7.00, to cover the cost of the tape, postage and packaging.

Hi-Res Package 3 - Copies of some Datamax UV-R1 Schematics

These schematics were used to come up with the Astrocade system upgrade package 1. Comparison of the schematics will show the similarities of the Astrocade upgrade with the Datamax UV-1R. For a complete set of Datamax UV-1R schematics and layouts (excluding power supply) contact DataMax Inc. I paid $30 for one set of prints (21 drawings). The notes on the attached Datamax schematics were added by myself, way back when I was for studying the schematics.

Hi-Res Package 4 - 44K Byte Dynamic RAM Add-On

This one-page instruction sheet uses three schematics in "Package 1 Astrocade System Upgrade" to make some deletions for this upgrade.

Add-on requires only +5V power supply. Refer to power supply schematic in Package 1. This add-on is recommended only for use with separate composite video and audio outputs between monitor/TV.

Hi-Res Package 5 - 12K Byte Static RAM Add-On

Static RAM does not require any refreshing or special timing circuitry. Data will remain intact as long as +5V is supplied to the board and the write protect switch is on. This feature allows the board to be disconnected from one computer and connected to a second computer or allow cartridge swapping without running loops. In either case, the data in Static RAM will remain intact (unchanged).

The Balcheck II display is optional and is used by Balcheck II software (not available at this time) to aid in troubleshooting the motherboard or static RAM. The videocade connector allows a videocade to be copied to tape. A videocade PC board, removed from its cartridge, is inserted in the videocade connector. Astrocade BASIC (or Bally BASIC) is then used to copy the contents of 6000-7FFFH to tape.

Incidentally, this add-on can be used with the Package 1 upgrade (connected to 50-pin expand header). This add-on requires only a +5V power supply.


Wouldn't it be great if someone could use this information that Michael Matte create to actually made a hi-res Astrocade?



0 user(s) are browsing this forum

0 members, 0 guests, 0 anonymous users