[vcf-midatlantic] Working Tandy 1000 or 2000

Kelly Leavitt kelly at catcorner.org
Thu Aug 30 20:18:02 EDT 2018


Found a 1000TX in the dungeon. Have to get it out.

Took a picture of U41 in my SX, which I believe is the the ROM. It is Tandy part number 8079015. Makers mark is a capital (and serrifed) GI. That does not agree with any ICs on the parts list.


Hope this helps.


My guess is the Tech Ref is based on 01.01.00. The later version of BIOS has a different internal part number.


Kelly


________________________________
From: Jonathan Gevaryahu <jgevaryahu at gmail.com>
Sent: Thursday, August 30, 2018 3:52 PM
To: Kelly Leavitt; Dean Notarnicola; vcf-midatlantic
Subject: Re: [vcf-midatlantic] Working Tandy 1000 or 2000

Interestingly, so far the tech manual has been correct about the sound chips.
The tech manual for the SX however claimed that it uses the "8040328" BIOS, which is version 01.01.00
but it uses a bios which is 01.02.00, with an unknown number? Maybe some SX machines shipped with the 8040328 and some with whatever the tandy part number is for the later bios?
Can you snap a pic of the bios chip in your SX?


On 8/30/2018 3:20 PM, Kelly Leavitt wrote:

OK, I'll see if I have the TX. Based on the (known unreliable) technical reference manual, the 1000TX uses the NCR 8496.


________________________________
From: Jonathan Gevaryahu <jgevaryahu at gmail.com><mailto:jgevaryahu at gmail.com>
Sent: Thursday, August 30, 2018 2:21 PM
To: Kelly Leavitt; Dean Notarnicola; vcf-midatlantic
Subject: Re: [vcf-midatlantic] Working Tandy 1000 or 2000

The 1000TX I've heard (but am not sure) uses an NCR8496, but again, just a rumor.

On 8/30/2018 10:23 AM, Kelly Leavitt wrote:

Just confirmed, my 1000SX has the SN76496 TI chip. I'll have to look at the others in this family.


________________________________
From: Dean Notarnicola <dnotarnicola at gmail.com><mailto:dnotarnicola at gmail.com>
Sent: Wednesday, August 29, 2018 11:48 PM
To: vcf-midatlantic
Cc: Jonathan Gevaryahu; Kelly Leavitt
Subject: Re: [vcf-midatlantic] Working Tandy 1000 or 2000

I just picked up an SX.  I'll check it in the morning

On Wed, Aug 29, 2018 at 11:13 PM Jonathan Gevaryahu via vcf-midatlantic <vcf-midatlantic at lists.vcfed.org<mailto:vcf-midatlantic at lists.vcfed.org>> wrote:
The problem is I've found that the parts lists in some of the Tandy
manuals is incorrect.

On 8/29/2018 10:11 PM, Kelly Leavitt wrote:
>
> OK, sorry I got that backward. I have an SX apart on the bench for
> some testing. I cannot find any chip with either part number. It is
> either hiding under a Tandy house number or part of the 2 big (for the
> time) ASICs. I'm pulling up the technical reference manual now.
>
>
> OK, according to the parts list on P51, U37A is an SN76496 Tone
> Generator. That agrees with page 7 of the schematic.
>
>
> I've attached screen grabs of these if they don't get stripped.
>
>
> You can find the tech ref for the 1000sx at
> ftp://ftp.mindcandydvd.com/pub/drivers/Tandy/Tandy_1000SX_Technical_Reference_Manual.pdf
>
>
> I'll verify the part number of IC U37A tomorrow.
>
>
>
> ------------------------------------------------------------------------
> *From:* Jonathan Gevaryahu <jgevaryahu at gmail.com<mailto:jgevaryahu at gmail.com>>
> *Sent:* Wednesday, August 29, 2018 9:18 PM
> *To:* Kelly Leavitt; vcf-midatlantic
> *Subject:* Re: [vcf-midatlantic] Working Tandy 1000 or 2000
> The TI chip is fairly well understood; the original Tandy 1000/1000HD,
> and the slightly enhanced 1000A used the 'real' TI chip, SN76496, for
> certain.
> Its possible that the EX (and maybe HX?) also used it, but unclear.
>
> The SX and TX (and maybe the HX?) SUPPOSEDLY used the weird NCR8496
> chip, which is what I need tested. (assuming wikipedia is correct,
> which it actually isn't regarding the SN76496 on the Tandy 1000/1000A...)
> The SL2, TL2, RLX, RSX use the PSSJ-3 ASIC, which would also be ok for
> testing, but ideally I'd like to run these tests on both the NCR8496
> and the PSSJ-3.
>
>
> On 8/29/2018 8:36 AM, Kelly Leavitt wrote:
>>
>> I have manyof the 1000 series computers (hx, ex, sx, sl, sl2, tl,
>> etc). Do you know which used the wonky TI chip? I can always start
>> opening them up.
>>
>>
>>
>> ------------------------------------------------------------------------
>> *From:* Jonathan Gevaryahu <jgevaryahu at gmail.com<mailto:jgevaryahu at gmail.com>>
>> <mailto:jgevaryahu at gmail.com<mailto:jgevaryahu at gmail.com>>
>> *Sent:* Wednesday, August 29, 2018 12:55 AM
>> *To:* Kelly Leavitt; vcf-midatlantic
>> *Subject:* Re: [vcf-midatlantic] Working Tandy 1000 or 2000
>> Another thing: I need to test against a tandy 1000-series with an
>> NCR8496 or PSSJ-1 asic in it, i.e. not the original tandy
>> 1000/1000a/1000hd, since they actually use a real TI SN76496 PSG
>> which actually behaves differently! (that's the whole reason I need
>> to do these tests, the behavior isn't consistent!)
>>
>>
>> On 8/29/2018 12:53 AM, Jonathan Gevaryahu wrote:
>>> Indeed, I was thinking of the 1000 series, not the 2000.
>>> I'm trying to figure the best way to run the tests from basic, i
>>> might need to mess around with dosbox to get the program written,
>>> since MAME has keyboard issues with the tandy machines (which I'd
>>> also love to fix...)
>>>
>>>
>>>
>>> On 8/28/2018 8:45 PM, Kelly Leavitt wrote:
>>>>
>>>> The 2000 and the 1000 were remarkably different beasts. The 2000
>>>> had a basic speaker that did beeps. There was a rumored TV board
>>>> but I have never seen one in the wild. Fun tidbit, the 2000 loaded
>>>> BIOS from floppy (a 720k 5.25 inch floppy). The built in ROM was a
>>>> simple boot loader.
>>>>
>>>>
>>>> The 1000 was mostly compatible with the XT/jr with some added sound
>>>> and graphics capabilities.
>>>>
>>>>
>>>> I have working models of the 1000 hear that I cant test with
>>>> Tandy's Basica if you'd like. My 2000's are iffy so I can't make
>>>> any promises. Send me the pokes you'd like to try.
>>>>
>>>>
>>>> Kelly
>>>>
>>>> kelly at catcorner.org<mailto:kelly at catcorner.org> <mailto:kelly at catcorner.org<mailto:kelly at catcorner.org>>
>>>>
>>>>
>>>>
>>>> ------------------------------------------------------------------------
>>>> *From:* vcf-midatlantic <vcf-midatlantic-bounces at lists.vcfed.org<mailto:vcf-midatlantic-bounces at lists.vcfed.org>>
>>>> <mailto:vcf-midatlantic-bounces at lists.vcfed.org<mailto:vcf-midatlantic-bounces at lists.vcfed.org>> on behalf of
>>>> Jonathan Gevaryahu via vcf-midatlantic
>>>> <vcf-midatlantic at lists.vcfed.org<mailto:vcf-midatlantic at lists.vcfed.org>>
>>>> <mailto:vcf-midatlantic at lists.vcfed.org<mailto:vcf-midatlantic at lists.vcfed.org>>
>>>> *Sent:* Sunday, August 26, 2018 5:16 AM
>>>> *To:* vcf-midatlantic at lists.vcfed.org<mailto:vcf-midatlantic at lists.vcfed.org>
>>>> <mailto:vcf-midatlantic at lists.vcfed.org<mailto:vcf-midatlantic at lists.vcfed.org>>
>>>> *Cc:* Jonathan Gevaryahu
>>>> *Subject:* [vcf-midatlantic] Working Tandy 1000 or 2000
>>>> Does VCF have a working Tandy 1000 or 2000 on display or in the
>>>> warehouse?
>>>>
>>>> I need someone with access to a working Tandy 1000/2000 to do some
>>>> poking from basic of the sound chip, since there's an issue I'm
>>>> running
>>>> into with a possible incompatibility of the Tandy 1000/2000 NCR8496
>>>> PSG
>>>> (sound chip) and the more common SN76489/SN76496 PSG which the
>>>> colecovision etc used.
>>>>
>>>> --


--
Jonathan Gevaryahu
jgevaryahu at gmail.com<mailto:jgevaryahu at gmail.com>
jgevaryahu at hotmail.com<mailto:jgevaryahu at hotmail.com>


--
Jonathan Gevaryahu
jgevaryahu at gmail.com<mailto:jgevaryahu at gmail.com>
jgevaryahu at hotmail.com<mailto:jgevaryahu at hotmail.com>


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