(Topic ID: 260925)

Eproms and Burners

By oldschoolbob

4 years ago


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  • Latest reply 3 months ago by slghokie
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    #7 4 years ago
    Quoted from oldschoolbob:

    Looks like the difference in EPROMS is the memory size. What is the most common size for pinball games?

    Those old Bally/Stern boards use 2k byte and 4k byte ROMs.
    2kB capacity are 9316 (PROM) and 2716 EPROM
    4kB capacity are 9332 (PROM), 2532 and 2732 (these two EPROMs have minor differences in pinouts)
    The 2532 is pin compatible to the 9332 PROM found on Bally -35 boards.
    2716 is NOT pin compatible with 9316 and requires board jumper mods for the different pinouts.
    2732 is NOT pin compatible with 9332 and requires board jumper mods for the different pinouts.
    2732 are generally cheaper/easier to get than 2532.
    The black plastic (non-window) PROMs found on those old Bally/Stern boards are either 9316 or 9332 PROMs.

    You can use 2532/2732 in place of 2716 by simply doubling the data.

    Boards with a ROM at U1 and U2 can be combined into a single 2532/2732 installed at U2 (with board jumper changes).

    EEPROMs = Electrically Erasable PROMs
    There are electronically erasable versions of 2716 which are 2816 and 28C16.
    There are NO electronically erasable versions of 2532/2732. You will have to use EPROMs.

    Quoted from oldschoolbob:

    I read the GQ-4X manual and it doesn’t say much about the power supply. The way I understand it a powered USB port should work but an external power supply would be like a backup in case the USB is not enough power. The manual doesn’t say what to use for external power. Would a wall-wart work? What voltage do I need? Those of you who have used the GQ-4x, what are you using?

    The EPROMs you're programming for those old boards require 21 - 25 volts. USB ports are limited to how much current they can provide when being boosted to those voltages so makes programming some chips unreliable. I don't use a GQ-4X programmer but in demo mode it advises that if write failures occur when programming these old EPROMs to use an external power pack. Their help guide specifications for the power pack is:
    9V DC, 200ma or above current
    I'd recommend getting a power pack.

    Quoted from oldschoolbob:

    I checked Marco and they seem expensive (3.00 each). But Jameco is 5.95 each. Where is everyone getting their chips?

    China.. They're $1 a piece. You can probably find local sources on ebay.
    Jameco are selling ST branded 2732. Guess what you're getting when buying from China.. Another pinball part supplier was selling counterfeit SCRs that had crossed over legs a year or two ago, and there's a thread today of another pinball part supplier potentially selling fake LM323 regulators. Didn't you also get a fake LM323 from a pinball part supplier a year ago?
    Other than GPE, I think you see where I'm going here.
    The EPROMs required for these old boards are long obsolete. You cannot buy brand new, you'll be getting used parts.

    Quoted from oldschoolbob:

    Why are there different programming voltages and which voltage are you suppose to use?

    The older EPROMs required a high voltage to program the cells and is partly based on the technology of the silicon die.
    2716/2532/2732 require 25 volts for programming
    2716A/2532A/2732A require 21 volts for programming
    You can get some 27C16B and 27C32B that will program at 12.5 volts but they are quite hard to come by now.
    Here are links showing pictures of many types of 2716 and 2732 EPROMs - some are marked with their programming voltage:
    http://cpucollection.ca/2716.htm
    http://cpucollection.ca/2732.htm

    Quoted from oldschoolbob:

    I understand there are other programs written to check other things on a board. Are those programs available to download or do I have to write them myself? I have no idea how to write programs and I don’t think it’s something I want to try to learn.

    I guy called Leon (RIP) wrote some diagnostic ROMs for a number of boards - they're available for download on PinWiki. There are others out there I believe, but I don't use any of them.

    #9 4 years ago
    Quoted from oldschoolbob:

    One thing i did catch is you don't use the GQ-4X.What programer do you use (probably some professional equipment)?

    I have some professional programmers (LabTools-48 and BK Precision 866C) but only use them for more specialised chips. It won't surprise you but I just use a cheap Chinese TL866A programmer for this stuff. It's small and portable.
    There's some caveats when programming 2716 chips where they need to be programmed multiple times but I'm used to it. The TL866A was made obsolete after too many counterfeits were being made. The latest counterfeit is this one which I bought recently as a cheap backup.

    ebay.com link: XP8710 USB Programmer Nand Flash 24 93 25 MCU Bios EPROM AVR IC Chip

    The TL886 was replaced with the TL886II+ but maximum programming voltage is 18 volts which isn't suitable for the EPROMs discussed here.

    Most programmers you buy these days include the ability to test 7400 series and 4000 series logic chips which can come in handy.

    #17 4 years ago
    Quoted from oldschoolbob:

    I’m hoping to invest under $200.00 for this adventure.

    That will be reality.
    $125.50 for the GQ 4x4 and an eraser:
    ebay.com link: GQ PRG 109 GQ 4X V4 GQ 4X4 Universal EPROM Programmer EPROM UV Eraser

    You can get 10pcs of 2716 or 2732 out of China for less than $8
    US wise these 27C32Q-200 look like a good deal - these only require 12.5V for programming.
    ebay.com link: PROM EPROM EEPROM EEROM UVPROM Modules

    Technically speaking you can skip getting 2716 EPROMs and just use 2732 instead (with the data doubled). They're the same price. I'm pedantic and still use 2716 where appropriate.

    Quoted from oldschoolbob:

    Some call the burner GQ 4X and others call it GQ 4X4. Is there a difference? Is the GQ 4X an older version? I can’t find a 4X – only 4X4’s.

    The 4x4 just means version 4 of the 4x

    Quoted from oldschoolbob:

    How do you double the program space – burn it twice or load the buffer twice. Is that easy to do?

    Load the lower half and upper half of the buffer with the same data then burn.
    Alternatively you can double the file before loading in the programmer software by copying it twice - in a Windows Command Prompt type:
    COPY /B ROM + ROM ROM2

    ROM refers to your source file. ROM2 will become your double sized ROM file.

    Quoted from oldschoolbob:

    Quench listed a couple of links of EPROMs. I’m guessing every manufacturer has their own part number for the same part. (This is always confusing for me). Is there any way to decipher what their part numbers refer to or do you have to check each data sheet?

    Quoted from oldschoolbob:

    I’m also finding the pin outs on EPROMs are different. Shouldn’t all Bally / Stern games have the same pin outs?

    For the most part, all 2716 have the same pinouts (except for Texas Instrument TMS2716 which has different pinouts - they were first to market at 2kB capacity but required 3 different programming voltages. Intel then came out with a single programming voltage so their solution won out). You won't come across any TMS2716 so don't worry.
    All 2732 have the same pinouts, likewise with all 2532.

    Quoted from oldschoolbob:

    Shouldn’t all Bally / Stern games have the same pin outs?

    That's what the board jumpers are for. PROMs versus EPROMs have different pinouts (except in the case of 9332B PROMs where 2532 EPROMs are a direct plugin replacement). Bally switched to 9332B around '81.

    Bally-17 and Stern MPU-100 require mods to use 2716 or 2732 EPROMs. Below I documented a simpler method to convert to 2732 that's less convoluted than the long time approach as listed on PinWiki. It also has the benefit of directly supporting *some* 2716 chips (listed on the last post).
    https://pinside.com/pinball/forum/topic/converting-a-bally-17-to-35-mpu-with-fo597-service-bulletin#post-5270218

    The PPS website lists the jumper settings for different ROMs on Bally boards here:
    http://www.planetarypinball.com/mm5/Williams/tech/bally_read1st.txt

    For Stern MPU-200 boards refer to the ROM jumper settings on the MPU-200 board schematics.

    #19 4 years ago

    It's recommended to place an opaque sticker over the EPROM window after programming to ensure any stray UV light doesn't affect the programmed cells.

    Quoted from pinfixer:

    Some say the light is harmful to the eye, others say not.

    The spec on your linked germicidal lamp says "CAUTION: can be very harmful to eyes and skin. DO NOT expose eyes or unprotected skin to these lamps. SERIOUS injury and blindness could result."
    My eraser warns against looking at the light.

    Quoted from pinfixer:

    Can you "over" erase a EPROM? Is there any risk of damaging an EPROM by exposing it to too much UV (erasing) radiation?

    Apparently yes. Over exposure to UV can render the EPROM un-programmable. How long is over exposure?, not sure.
    Is your lamp connected to a timer?
    Did you install a reflector behind the lamp?
    How far from the chips are you placing the lamp? Specs on all the EPROMs I've seen recommend 1" (2.5cm).

    I erase my EPROMs for about 15 minutes.

    The typical erasure info I see in EPROM spec sheets say:

    The recommended erasure procedure for the M2732A is exposure to shortwave ultraviolet light which has a wavelength of 2537 Å (254nm). The integrated dose (i.e. UV intensity x exposure time) for erasure should be a minimum of 15W-sec/cm2. The erasure time with this dosage is approximately 15 to 20 minutes using an ultraviolet lamp with 12000 µW/cm2 power rating. The M2732A should be placed within 2.5cm of the lamp tubes during erasure.

    #21 4 years ago
    Quoted from gdonovan:

    I have a stand alone 4 chip erasing unit with timer setting, I always use the minimum setting of 5 minutes due to warnings about excessively exposing chips. Worse case one or two chips need to get another five minute pass when I do another batch of four.

    The erasure time depends on the light intensity of the UV lamp. I must admit my eraser is about 25 years old.
    If yours only does 4 chips, is it one of the cheap Chinese erasers commonly listed on ebay?

    UV-Eraser_Grey2.jpgUV-Eraser_Grey2.jpg
    UV-Eraser_White2 (resized).jpgUV-Eraser_White2 (resized).jpg

    #26 4 years ago
    Quoted from pinfixer:

    Yes the desk lamp has a white reflector basically giving the light 180 degrees.

    My eraser has a semicircle chrome metal reflector above the lamp.

    Quoted from pinfixer:

    I have found TI TMS2732A are the best at erasing / reprogramming cycles but are painfully slow to program.

    The slowness could be an issue with the algorithm of your programmer?? TMS2732A spec is pulse program at 11ms max. Rough calculation is about 40 seconds max to program?

    The MiniPro TL866 programmer has an incorrect algorithm for 2716 and 2732 EPROMs with programming pulse way too short. I believe it's the reason 2716 don't program properly first time, rather than the fact the programmer doesn't have 25V support. My LabTools-48 programmer takes nearly 2 minutes to program 2716 chips and has no issue. The MiniPro takes less than 10 seconds and produces an unreliable result.

    Quoted from pinfixer:

    I prefer pulls as other posters have said the Chinese knock-offs are not very good quality wise.

    I haven't received any bad 2732 from China. The last two recent batches of 2716 I bought from China were used pulls with original markings and some label glue still on them with different date codes from the early '80s (i.e. not remarks).

    #29 4 years ago

    Bally ROM detailsBally ROM details

    Quoted from oldschoolbob:

    I’m not totally against buying from China – just very cautious. (by the way can you catch Coronavirus through the mail?)

    Interesting question

    Note China is just coming out of New Nears vacation. There's going to be a huge backlog on purchases and shipping so you might be waiting longer than normal to get your parts.

    Many AliExpress vendors source their parts from the same suppliers. You're not (rarely are) buying direct from the source. If it doesn't cost you anything (much) choose a vendor with faster shipping and see if they have any customer reviews maybe with pictures included.
    For the past few years, ST branded 2716 were being supplied but it looks like they've just about dried up and are now supplying different manufacturer parts as used pulls and no longer remarking them.

    Quoted from oldschoolbob:

    Are you saying if I burn ROMS for Bally-17’s or Stern-100’s that I must make modifications to the MPU? What EPROMs would be a direct replacement?

    You must modify these boards, there is no direct plugin replacement for the original 9316 PROMs

    Quoted from oldschoolbob:

    What’s the difference between 2532 and 2732?

    Three pinouts are different between 2532 and 2732 chips - see pins 18, 20 and 21 in the diagram below.
    /CE = Chip Enable (active low)
    /OE = Output Enable (active low)
    Vpp = Voltage Program pin
    Axx = Address line xx
    Ox = Data Output line x

    EPROMs1.gifEPROMs1.gif

    Quoted from oldschoolbob:

    how do you know which ROM to use? I just looked a couple of boards I’m working on (Bally-17 and Bally-35) and none say 2716 or 2732. Why can’t they make this easy?

    When you download ROMsets from IPDB, look at the file size of each ROM.

    2kB capacity are 9316 (PROM) and 2716 EPROM (16 kilo bits = 2 kilo Bytes)
    4kB capacity are 9332 (PROM), 2532 and 2732 EPROMs (32 kilo bits = 4 kilo Bytes)

    2532 are a drop in replacement for 9332. Bally used 9332 chips from around Flash Gordon onwards. Before this they used 9316 PROMs though on some games before Flash Gordon, 2716 EPROMs was used at U1 and U2.
    Stern mostly stayed with 9316 PROMs but did use 2716 EPROMs on some MPU-200 games.

    oldschoolbob can you please post a single picture of your Eightball MPU board clearly showing both ROM chips for my reference? Thanks.

    #33 4 years ago
    Quoted from oldschoolbob:

    I looked over Quench’s post on converting -17 to -35. It doesn’t look too complicated and I’m sure I’ll be doing some converting soon. However, (as they say) a picture is worth a thousand words. Anyone have any photos of this conversion? Also what kind of wire do you use?

    I've modified two boards for test. I just used any wire handy. I don't actually run the short wire shown in the mod - instead I just use a lead clipping very close to the leg and cut trace to bridge them. I'll post a picture later. Somebody in this thread sent me a picture of how they did the mod - I'll let them decide if they want to post their picture here

    Quoted from oldschoolbob:

    thanks for the photo explaining the ROM type. That is very helpful. Sometime back you posted a list of Stern ROM numbers for which games. (I think it was German) Very helpful and I have it in my pinball file. Is there a similar list for Bally games?

    For Bally, the ROM part numbers are listed in their parts catalogs which you can download from PinWiki:
    https://pinwiki.com/wiki/index.php?title=Bally/Stern#Parts_Catalogs

    Quoted from oldschoolbob:

    That would be the -17 board? It is still intact. I'll take some photos tomorrow.
    However I have these photos of a Bally Eightball I worked on sometime ago.
    Let me know if you need more photos.

    Thanks, those Eightball MPU board pictures have the original version ROMs. The Eightball ROM pictures you attached in post #27 were the later version Eightball ROMs that aren't documented (not even in their parts catalogs) as being used together. That's the reason I'd like a picture of that board to keep for reference as evidence they co-existed. I'm a part of a separate documentation project.

    Quoted from oldschoolbob:

    Then wouldn't a 2516 be a drop in replacement for 9316?

    2516 is not pin compatible with 9316. I want to be clear about one aspect of the 93xx series PROMs.
    The 9316 has three CS (Chip Select) pins. The active logic levels per CS pin can be programmed at factory. If Bally had the foresight they could have ordered 9316 chips that were compatible to the 2716 pinout. Instead they ordered 9316 that were pin compatible with previous gen smaller size PROMs.
    The 9332 has two CS (Chip Select) pins. Bally chose to order them to be compatible with 2532 pinouts. Don't quote me on this but from memory, the 9332 PROMs used on Williams boards are pin compatible with 2732 chips.

    The attached PDF datasheet contains both the 9316 and 9332 specs and details about why the CS pins were programmable to simplify product design.

    93xx_PROMs.pdf93xx_PROMs.pdf

    #40 4 years ago
    Quoted from oldschoolbob:

    Hope these help - need more just let me know.

    Thankyou Bob, those pics are great!

    Quoted from pinfixer:

    I just burned (programmed) a set of Mata Hari code on two TI2732A chips. Took exactly 3:30 each. This is on a Needhams EMP-21.

    Here's the issue. Your programmer probably has a generic 2732 algorithm where they used the standard timing spec from Intel 2732 of 45-55ms programming pulses. 2732 has 4096 bytes. 4096 times 50ms programming pulse for each byte equals 3:24 minutes.
    TI TMS2732 program pulse spec is 11ms max so it should be taking 45 seconds to program. Ring up Needham tech support and tell them to fix it

    BTW since you're the early Bally enthusiast, it doesn't seem widely known that MPU boards for 7 digit games have a different resistor in the display interrupt generator circuit compared to the 6 digit game MPU boards. See here:

    https://pinside.com/pinball/forum/topic/two-bits-mpu-with-flickering-strobing-displays-#post-5408121

    and here a few posts down for pictures.

    https://pinside.com/pinball/forum/topic/two-bits-mpu-with-flickering-strobing-displays-#post-5408417

    3 months later
    #53 3 years ago
    Quoted from RoyF:

    How do the Checksums work for EPROMs?

    The checksum is usually the sum of all bytes you're programming.

    If you're burning the same file to two EPROMs of the same size/bit orientation, the checksum will be the same.
    So in your case the same file should show exactly the same checksum when burning an AMD AM27512 or a ST M27512 since these EPROMs are the same capacity and are equivalent.

    2 years later
    #62 1 year ago
    Quoted from slochar:

    There is an eeprom version of the 256 that does not work IIRC.

    You might be thinking of the AT28C256 which has a slightly different pinout to 27256

    SST27SF256 are a EEPROM version that looks pin compatible. Cheap out of China.

    #66 1 year ago
    Quoted from barakandl:

    But ive seen some flash memory I end up not buying because they are only guaranteed to hold memory for ten years after a burn

    Data retention spec for early EPROMs like 2716 was 10 years too - the spec was usually at maximum ratings.
    I haven't seen many of these 40 year old games with EPROMs suffering bit rot though.

    The concern these days is the current crop of cheap programmers not burning cells with enough margin that will result in reduced data retention (data loss in years rather than decades).

    The below article is taken from "Intels 1984 Memory Components Handbook" and discusses the move to intelligent/fast EPROM programming and dealing with verifying cells at different voltages to ensure good margins. May be an interesting read for some.

    EPROM_Intel_Versatile_Algorithm_Equipment_Cut_EPROM_Programming_Time.pdfEPROM_Intel_Versatile_Algorithm_Equipment_Cut_EPROM_Programming_Time.pdf
    #68 1 year ago
    Quoted from Tuukka:

    I think I have never seen a pinball EPROM suffering from bit rot even though some are 40 years old.

    It happened with my Black Hole. I turned it on after a few months of no use and was suddenly getting the 7641 ROM error on the displays. The factory game 2716 EPROM had some bad bits. This was probably about ten years ago.

    Quoted from Tuukka:

    This is probably my first EPROM project from 1985. A terminal from Intel data book application note, for my first homemade micro. The 2716 EPROM's are still OK!

    Impressive!

    #70 1 year ago
    Quoted from Tuukka:

    Anyway, the BH EPROMs might have been quite early production 2716's so no wonder that with a "versatile algorithm" they might fail only after 40 years

    I still have that chip, it was a Hitachi 2716. No date code but must be '79 or '80.

    Quoted from Tuukka:

    As for my impressive terminal board... cover your eyes and be very careful looking at this rats nest at the back side... Prototyping boards were expensive then.

    That is a work of art!

    2 weeks later
    #77 1 year ago
    Quoted from interconnect:

    The W27C512 will work in place of a 27xxx?

    Yes, provided you replicate the data. The address lines do not change position.

    Larger ROMs use pins which lower capacity DIP28 ROMs didn't, or programming signals were moved which don't affect normal read operations.

    W27E512 are functionally the same as W27C512 and also the same price. The 'E' in the part number more clearly indicates them as EEPROM.

    Here's a pin definition diagram I use for reference:

    MPU-35a_27128ROM.pngMPU-35a_27128ROM.png

    10 months later
    #84 4 months ago
    Quoted from gdonovan:

    Anyone have a reliable source for 2732(a)'s? I have a batch I purchased off Ebay months ago and not a single one will program. Either with my newer burner or an ancient Pocket Programmer parallel port model. All of them fail around the 2% though a single one made it to 54%

    Probably 2 or so years ago there were counterfeits out of China of ST branded 2732A chips that were actually National Semiconductor 2732B chips based on the internal silicon die. These use a programming voltage of 12.5V, not 21V as printed on the chip. The below picture was sent to me from frunch of said part - looks the same as some of the ones Joydivision posted: I don't remember whether programming them at 21V blew them. Try programming them at 12.5V

    2732_Remark.jpg2732_Remark.jpg

    #91 4 months ago
    Quoted from gdonovan:

    I tried all three voltages with the older burner and it made no difference.

    You likely damaged them all programming at the remarked/rebranded voltage obviously being higher than what the chips really wanted.

    Quoted from Joydivision:

    So the chinese M2732A chips need to be programmed at 12.5V to start with, if that doesn't work then try 21V & then 25V as you don't know really what they actually really are. Then some won't work regardless.

    Here's a web site showing some EPROM silicon die images - click on the 2732 link on the left frame. Does that National Semiconductor NM27C32BQ-150 die look familiar to the above ST remarked chips? Programming voltage is marked as 12.75V

    http://brainstones.narod.ru/collection_uv_eprom/_uv_left.htm
    http://brainstones.narod.ru/collection_uv_eprom/2732.htm

    When you match the silicon die, the datasheets will tell what programming voltage and pulse width the chip needs.
    Here's that genuine NS part picture for reference:

    2732_ns_nmc27c32bq_150.jpg2732_ns_nmc27c32bq_150.jpg

    #93 4 months ago
    Quoted from Joydivision:

    that's a great resource to definitively determine what chip you have & the programming voltage.

    There used to be a great site (cpucollection.ca/2732.htm) that had silicon die pics of nearly every 2732 but sadly it died three years ago.

    Quoted from Joydivision:

    Also the other NS part NM27C32Q-45 is identical to the ST remarked eproms with the larger die that some have in the above pics..

    Well that one is kind interesting. The larger die matches the Eurotechnique ETC2732Q-45 chip. They either OEM'd the part from NS or vice-versa. At some point Eurotechnique became Thomson and later SGS merged with Thomson to become ST. So that one may be an origin from a former ST company. The ETC2732Q datasheet specifies it's a 25V program part, and the NS NM27C32 datasheet says the same. The Q suffix in the part number refers to ceramic DIP package.

    Quoted from Joydivision:

    I have looked very closely under magnification & the chips I have & they are not used, sanded & refinished chips, they are brand new for sure.

    Are you referring to the picture you posted above? They are definitely are all remarks. Considering there's different silicon die in the mix they cannot all really be manufactured on the same date code (also no way they were made in 2007) and with identical markings.

    Quoted from Joydivision:

    Would these be then newly manufactured chips based on the NS silicon die(s) & then marked ST to simply sell for more than an NS chip?

    I doubt anyone is newly manufacturing 2732 EPROMs. If you're talking about other ST 2732 EPROMs that gives you this suspicion, post some pics so we can have a look.

    #96 4 months ago
    Quoted from barakandl:

    Whenever I peal a label off a 27C160 and see it is the giant sized window version, I go dammit. I don't think I've successfully re-used one of those yet.

    Yeah, I had the same issue with the first 27C160 I had and every time I hit the program button I got a little further. Took something like 100 programs to reach the end with a successful write. In hindsight I should have tried bumping up the program voltage a little.

    The small die 27C801 seem to program much easier than the larger die units.

    Quoted from barakandl:

    Been meaning to try some AT28C16 salvages. Strange and unfortunate they didn't make AT28C32... skipped over to 64K

    They ran out of pins for the /WE signal to make a AT28C32.

    Quoted from Joydivision:

    One thing which is weird is one chip has 2 blobs of silicon or similar material as per pic.

    Hmm, I always thought those grey silicon blobs were from factory. Looking at a bunch of local NOS ST M2732A a friend gave me, none of them have those blobs.

    These were the last ST M2732A parts I got from China in August 2023.
    https://www.aliexpress.com/item/1005004784226290.html
    Their picture is of a remark, but I received genuine not remarked with original '88 date code parts with small silicon die - even still have the glue from the removed window label. Legs have been re-tinned. They don't have the grey silicon blobs. But I haven't tried them yet.
    There is no guarantee an order placed today will be the same.

    Recently I bought some 74HCT00 SMT parts from an AliExpress seller. They came as fake marked Philips chips but worked fine. I ordered more from the same seller and got genuine Philips parts with all sorts of date codes in the 90's. Then I ordered more and got the same as the first batch fake Philips marked parts.
    I also ordered 74HCT00 from other sellers and received NXP 74HC00 parts (i.e. HC, not HCT)
    It's a lottery what you get.

    #100 4 months ago
    Quoted from gdonovan:

    Marco looks to be selling remarked chips.

    The reality is it's probably difficult/expensive finding real NOS or used pulls in the US in decent quantity anymore. Guesstimate they went out of production in the 90's.

    Quoted from gdonovan:

    The large core would not program AT ALL regardless of voltage.

    That wide core silicon die looks like an AMD 2732B chip. AMD 2732B are available through China like ST parts. I have some here that work ok, but NOT in a XGECU TL866ii+ programmer - it has a bug the manufacturer has ignored fixing.
    Chinese clearly have no idea about these EPROMs. There is no such thing as a 2732A with 12.5V programming.
    2732 = 25V programming voltage
    2732A = 21V programming voltage
    2732B = 12.5V programming voltage

    2732_amd_am2732bdc.jpg2732_amd_am2732bdc.jpg

    #102 4 months ago
    Quoted from gdonovan:

    They are advertising they are pulls,

    They are pulls - pulls done in China and then remarked.

    You're currently viewing posts by Pinsider Quench.
    Click here to go back to viewing the entire thread.

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