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2026-01-27 by Raf Wlodarczyk
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
2026-01-27 by Roman Sowa
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 > ________________________________________________________ > This is the Synth-diy mailing list > Submit email to: Synth-diy@synth-diy.org > View archive at: https://synth-diy.org/pipermail/synth-diy/ > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy > Selling or trading? Use marketplace@synth-diy.org
2026-01-27 by Raf Wlodarczyk
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@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 > > ________________________________________________________ > > This is the Synth-diy mailing list > > Submit email to: Synth-diy@synth-diy.org > > View archive at: https://synth-diy.org/pipermail/synth-diy/ > > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy > > Selling or trading? Use marketplace@synth-diy.org
2026-01-27 by grant musictechnologiesgroup.com
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@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 >>> ________________________________________________________ >>> This is the Synth-diy mailing list >>> Submit email to: Synth-diy@synth-diy.org >>> View archive at: https://synth-diy.org/pipermail/synth-diy/ >>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy >>> Selling or trading? Use marketplace@synth-diy.org > ________________________________________________________ > This is the Synth-diy mailing list > Submit email to: Synth-diy@synth-diy.org > View archive at: https://synth-diy.org/pipermail/synth-diy/ > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy > Selling or trading? Use marketplace@synth-diy.org
2026-01-27 by jpdesroc@oricom.ca
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@synth-diy.org> De la part de grant musictechnologiesgroup.com Envoyé : 27 janvier 2026 14:54 À : synth-diy@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@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 >>> ________________________________________________________ >>> This is the Synth-diy mailing list >>> Submit email to: Synth-diy@synth-diy.org View archive at: >>> https://synth-diy.org/pipermail/synth-diy/ >>> Check your settings at: >>> https://synth-diy.org/mailman/listinfo/synth-diy >>> Selling or trading? Use marketplace@synth-diy.org > ________________________________________________________ > This is the Synth-diy mailing list > Submit email to: Synth-diy@synth-diy.org View archive at: > https://synth-diy.org/pipermail/synth-diy/ > Check your settings at: > https://synth-diy.org/mailman/listinfo/synth-diy > Selling or trading? Use marketplace@synth-diy.org ________________________________________________________ This is the Synth-diy mailing list Submit email to: Synth-diy@synth-diy.org View archive at: https://synth-diy.org/pipermail/synth-diy/ Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy Selling or trading? Use marketplace@synth-diy.org
2026-01-27 by 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@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@synth-diy.org> De la part de grant musictechnologiesgroup.com > Envoyé : 27 janvier 2026 14:54 > À : synth-diy@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@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 >>>> ________________________________________________________ >>>> This is the Synth-diy mailing list >>>> Submit email to: Synth-diy@synth-diy.org View archive at: >>>> https://synth-diy.org/pipermail/synth-diy/ >>>> Check your settings at: >>>> https://synth-diy.org/mailman/listinfo/synth-diy >>>> Selling or trading? Use marketplace@synth-diy.org >> ________________________________________________________ >> This is the Synth-diy mailing list >> Submit email to: Synth-diy@synth-diy.org View archive at: >> https://synth-diy.org/pipermail/synth-diy/ >> Check your settings at: >> https://synth-diy.org/mailman/listinfo/synth-diy >> Selling or trading? Use marketplace@synth-diy.org > > ________________________________________________________ > This is the Synth-diy mailing list > Submit email to: Synth-diy@synth-diy.org View archive at: https://synth-diy.org/pipermail/synth-diy/ > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy > Selling or trading? Use marketplace@synth-diy.org >
2026-02-04 by Raf Wlodarczyk
I used the "Orphan Programmer". Not many devices will program parts with -41V :) This will be a read only situation, the PROM isnt written to when in use
> On 01/27/2026 2:53 PM EST grant musictechnologiesgroup.com <grant@musictechnologiesgroup.com> wrote: > > > 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@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 > >>> ________________________________________________________ > >>> This is the Synth-diy mailing list > >>> Submit email to: Synth-diy@synth-diy.org > >>> View archive at: https://synth-diy.org/pipermail/synth-diy/ > >>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy > >>> Selling or trading? Use marketplace@synth-diy.org > > ________________________________________________________ > > This is the Synth-diy mailing list > > Submit email to: Synth-diy@synth-diy.org > > View archive at: https://synth-diy.org/pipermail/synth-diy/ > > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy > > Selling or trading? Use marketplace@synth-diy.org > > > ________________________________________________________ > This is the Synth-diy mailing list > Submit email to: Synth-diy@synth-diy.org > View archive at: https://synth-diy.org/pipermail/synth-diy/ > Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy > Selling or trading? Use marketplace@synth-diy.org