[sdiy] PROM Replacement for Spider

[grant musictechnologiesgroup.com]

I believe this 512-bytes device requires -40v for programming (although 
other references say 5v, I highly doubt that). It seems to be targeted 
specifically at expanding the memory of the 8048 (IM80c48) judging by 
the fuzzy schematic.  One would be hard pressed, I think, to find a 
programmer that does this part. So, assuming you have or can extract the 
data, a newer device is definitely the way to go.

Spyder:
https://www.timstinchcombe.co.uk/synth/gnat/spider_schematic.JPG

Here's a guy using a 2732 for EPROM expansion of the 8048, so it's part 
way there...
https://github.com/jim11662418/Intel_8048_Single_Board_Computer/

GB


On 1/27/2026 12:15 PM, jpdesroc at oricom.ca wrote:
> That's what I use for programing all my special chips .
> https://www.aliexpress.com/p/tesla-landing/index.html?scenario=c_ppc_item_bridge&productId=4000206420694&_immersiveMode=true&withMainCard=true&src=google-language&aff_platform=true&isdl=y&src=google&albch=shopping&acnt=272-267-0231&isdl=y&slnk=&plac=&mtctp=&albbt=Google_7_shopping&aff_platform=google&aff_short_key=UneMJZVf&&albagn=888888&&ds_e_adid=&ds_e_matchtype=&ds_e_device=c&ds_e_network=x&ds_e_product_group_id=&ds_e_product_id=fr4000206420694&ds_e_product_merchant_id=107687892&ds_e_product_country=ZZ&ds_e_product_language=fr&ds_e_product_channel=online&ds_e_product_store_id=&ds_url_v=2&albcp=23049072419&albag=&isSmbAutoCall=false&needSmbHouyi=false&gad_campaignid=23043000363
>
>
> -----Message d'origine-----
> De : Synth-diy <synth-diy-bounces at synth-diy.org> De la part de grant musictechnologiesgroup.com
> Envoyé : 27 janvier 2026 14:54
> À : synth-diy at synth-diy.org
> Objet : Re: [sdiy] PROM Replacement for Spider
>
> What did you use for a programmer!? That's a pretty unique (oddball)
> part: 512 *bytes*.  No matter what parallel chip you use, it's going to require an adapter of some sort.  2732 looks closest, assuming your programmer can handle it. Otherwise I guess it doesn't really matter.
> How are the control lines E1*, E2*, S* attached? One for chip select and the other two grounded (or perhaps one to an address line)?
>
> GB
>
> On 1/27/2026 8:39 AM, Raf Wlodarczyk wrote:
>> The digiky ones come from Rochester and ALL the ones (i bought 50 of
>> each type) I got from them were bad, partial writes, wouldnt clear
>> etc.  I'll look at the AT27, thanks for the suggestion
>>
>>> On 01/27/2026 11:26 AM EST Roman Sowa <modular at go2.pl> wrote:
>>>
>>>    
>>> DigiKey has a thousand of them, but anyway, I wouldn't buy them
>>> because of the price and age.
>>> Whenever I need to replace old EPROM I pick most common, cheapest and
>>> easy to get OTP EPROM, which usually is AT27C256. It has 28 pins so 4
>>> of them will be outside of the socket, which typically can fit on the
>>> old board without pushing other components. After programming just
>>> wire 5 pins together: 1,2,26,27,28
>>>
>>> Or you may fance making breakout board for PLCC EPROM
>>>
>>> forget about buying newly made EPROM smaller than 256kb
>>>
>>> Roman
>>>
>>> W dniu 2026-01-27 o 16:16, Raf Wlodarczyk pisze:
>>>> Hello list,
>>>>
>>>> The supply of the IM6654 PROM i use in my Spider clone has dried up and was wondering if anyone had suggestions on how to use a modern part for a replacement.  IM6654 is a 8x512B device so could using a AT28C512 on an adapter do the trick?  My PROM/EEPROM knowledge is limited so any help would be greatly appreciated.
>>>>
>>>> -R
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