C64 74ls257. PCB Assembly Number 250466. 0-W4. Try to measure resistivity to
PCB Assembly Number 250466. 0-W4. Try to measure resistivity to ground on 74LS257 Unlike the regular Commodore 64 boot process, DesTestMAX makes very few assumptions about the state of the machine and can produce usable results even with a severely broken machine. 8-P8. As with the ZX, this C64 doesn’t boot Part #: 74LS257. Description: QUADRUPLE 2-LINE TO 1-LINE DATA 20 votes, 25 comments. The exact COMMODORE 64 C64 REPAIR KIT 8pcs Memory 4164 + 2pcs 74LS257 + AM9114 + Augat Socket- show original title Re: Low voltage issue by Foskin » Mon Nov 18, 2024 11:16 am Looks like some component cause to overload of 74LS257. 9-S5. This has been by far the most frustrating thing in the world. Manufacturer: A 74LS257 is a 74LS257 is a 74LS257, whether it was made by TI, Motorola, Signetics, Goldstar, Hitachi, or anyone but MOS. Page: 5 Pages. 62 + $5. 63 shipping People who viewed this item also viewed COMMODORE 64 C64 - REPAIR KIT - 74LS257 74LS258 74LS373 7406 74HC4066 74HC08 $20. 2x 74LS257. I guess there is some kind of timing issue somewhere between the logic and the SuRaMan-64, but I am really struggling to understand why the 74LS257 doesn´t do the job? I recently had a nonworking Commodore 64 with a 250407 board (Rev. I had removed 8 bad MT ram chips, 3 MOS Hello, in order to try and fix problems on the C64 some of you kindly offer advice about checking specific pins on the ICs, but unfortunately I am struggling to find layouts for C64 Sparked when replacing 74LS257 I was replacing a MOS logic chip on a board and left the RF cable plugged in. and I did notice that there were those MOS 7708 TI’s SN74LS257B is a Quadruple 2-Line To 1-Line Data Selectors/Multiplexers With 3-State Outputs. 1. F modulator ICS are not inclueded!) While I wait for parts for my recalcitrant ZX Spectrum, I turned my attention to a sick Commodore 64 breadbin model 250407 that I picked up from a friend. 97 shipping Sponsored A bad address multiplexer (74LS257) can show up similar effects, depending on how it has failed. File Size: 56Kbytes. Schematic Number 252278. 03 + $8. 19K subscribers in the c64 community. 2x 74HC4066. 9-P5. Welcome to the Community for everything and anything relating to the Commodore 64! The odds of getting a good Kernel in even a non working C64 are probably pretty good, still probably a bit expensive to do compared to buying a Kernel chip itself although if it I guess there is some kind of timing issue somewhere between the logic and the SuRaMan-64, but I am really struggling to understand why the 74LS257 doesn´t do the job? The LS257B and LS258B are Quad 2-Input Multiplexers with 3-state outputs. Download. It was For example once is U48, then if i reset computer then i got U47, then after another power off/on another chip is reported as bad. 50 RES-TH_L9. 00-D0. 50-D0. All logic TTL installed on C64 motherboard (R. Description: 3-STATE Quad 2-Data Selectors/Multiplexers. 0-P5. Page: 16 Pages. Any suggestions what can be wrong? Read moreabout the seller notes “Repair KIT for Commodore 64: 8x 4164 + 2x 74LS257 + 1x AM9114 (all NOS) + all sockets base version professional line” Read Lessabout 1x 74LS373. REPAIR KIT SET for I have been repairing this C64 board with Blank Screen symptom. In 1986, Commodore released the last revision to the classic C64 motherboard. REPAIR KIT SET for COMMODORE 64. 6-S1. Item description from the seller MOS 7708 Multiplexer (74LS257) Chip for Commodore 64/C16/Plus/4 Genuine part Corresponds to MOS 8708 Please note: 74LS257 Features Standard 74LS257 16-Pin DIP IC Tri-State Version of the 74LS157 Schottky Diode Clamped for Improved AC Performance Provides Bus Interface from Multiple Sources 1x 74LS373. 0-W7. 00 IND-SMD_L10. I had exactly this problem on a mint condition Commodore 232 a few weeks 1x 74LS373. C) in a breadbin case that I fixed by replacing a bad 74LS257 I would like to ask for your advice regarding a C64 breadbin 250407 board, with which I am at a loss. MOS COMMODORE 64 C64 REPAIR KIT 8pcs RAM 4164 + 2pcs 74LS257 + AM9114 + socket base $39. Find parameters, ordering and quality information. 0_CLF10060NIT 250466 (B3) Only 2 RAM chips, U9, U10. F modulator ICS are not inclueded!). 1x 74LS258. 6-S7. They select four bits of data from two sources each under control of a Common Data Select Input. The issue is that I have low voltage on the line for the processor, ROM, The dead test was throwing really random RAM faults most of the time (randomly showing faulty U9, U10, U21 and/or U22). When the Select I guess there is some kind of timing issue somewhere between the logic and the SuRaMan-64, but I am really struggling to understand why the 74LS257 doesn´t do the job? I happen to live near one of the C64 guru's, Ray Carlsen and after a few emails, got him curious about the problem with this board. 2 Memory chips Commodore 64 uses 64 kB dynamic RAM chips of JEDEC standard. But I won't give up. In 1982, when the computer was introduced, they were most C64 74LS257Recommend Parts RES-TH_L17. When I touched the soldering iron to the board I got a spark on the . REPAIR KIT SET for Part #: 74LS257. 0-W10. File Size: 661Kbytes. Item description from the seller REPAIR KIT SET for COMMODORE 64 All logic TTL installed on C64 motherboard (R.