Commodore 64 Chips
Custom chips and discrete logic as used in the C64. The logic and memory chips will generally be new / unused, whilst custom chips (SID, VIC, CIA, 6510 etc) will have been harvested from boards and tested. There are many C64 fault finding pages and videos on the net, and I have put up some brief info myself here. Products:
Click on the product thumbnail for an enlarged view.
2114 Colour RAM (IC "U6" in breadbin, "U19" in C64C)
- Unused, old stock (not soldered) chips in good condition.
- Tested before dispatch.
- Note: Depending on supplies, equivalent chip may be sent (TMM314, LC3514A etc)
Typical symptoms when faulty in C64:
- Incorrect, random or flickering colour attributes on power up.
8K / 4K 24-pin switchable ROM replacement module
- Replaces 24-pin 8K (and 4K*) ROMs that have the standard EPROM pin out (eg: TMS 4764) and an active low output select pin, such as the breadbin C64's Kernal, BASIC and Character ROMs
- Has an onboad switch allowing two different ROM images to be selected, if desired.
- Uses a very low power modern EEPROM chip.
- Please email me the ROM images you require on the module after purchase.
- Note: The module cannot be reprogrammed in a standard EPROM burner as it requires a special interface to set up.
* Regarding 4K ROMs: As long as pin 21 on the PCB taking a 4K ROM is tied high or low (ie: not left floating) no PCB modification is required (and if it is floating, just connect it to pin 24 or pin 12 - either is fine). (In the breadbin C64, the Character ROM (U5) is 4K, and pin 21 is pulled low already on the PCB. The BASIC (U3) and KERNAL (U4) ROMs are 8K.
251913-01 BASIC/KERNAL ROM for C64C *De-soldered*
- 28 Pin combined BASIC/KERNAL ROM at U4 in the C64C
- Desoldered, and re-tested: OK
CMOS 4066 IC
- As used at IC locations U16 and U28 in the breadbin C64, and at U21 in the C64C
- Common symptoms when U16 is faulty: Colour problems such as random colour “chequerboard” pattern on screen or no colour.
- Problems when U28 is faulty: Paddle controller issues.
41464 / 4464 RAM Chip
- Organization: 64K x 4, Speed 120ns, Package: 18 pin DIL
- New, old stock (not desoldered) - all tested before dispatch.
- As used on late revision motherboards of Commodore 64, Spectrum +2A/+2B/+3
- Depending on stock, "4464" types may be supplied - these are the same RAM chips but with a different part number.
4164 RAM Chip for Breadbin C64 (excluding p/n: 250466 boards) Also used in the Amstrad CPC464 etc.
- Organization: 64K x 1, Speed: 150ns or faster. Package: 16 pin DIL
- As used in all but the last "breabin" C64 board (PCB p/n boards have 2 x 41464s instead of 8 x 4164s)
- Unused, clean, old stock parts (all chips tested for 2 hours before dispatch)
- Also used in the Commodore +4, Amstrad CPC 464 etc (replacing 4264 types)
Faulty RAM chips in the C64 often result in an "Out of Memory" error on boot or less than 38911 bytes free. A crude but often effective way to test which chip is bad, is to "piggy-back" a working chip on each RAM chip one at a time. If the error goes away or at least changes, there's a good chance that chip is faulty.
6510 CPU Chip
- Removed from a socket and tested in working board - chip has not been soldered.
- When these chips fail, common symptoms can be: Blank screen, No border, Cartridge doesnt work, Certain programs lock up.
6526 CIA chip for Commodore 64
Removed from an IC socket and tested in a working board - chip has not been soldered.
Some typical faults that can occur when these chips are bad in a C64 include:
- Keyboard stops responding
- No cursor / stops blinking
- Joystick doesn't work correctly
- "Device not present" error when accessing disk drive
- Disk drive continues to search when trying to load
- User port does not function
- After a few minutes, characters all over screen
- Certain programs freeze
- No response when loading from tape
If your board has socketed chips, a simple way to test the 6526 CIA chips is to swap over U1 and U2 (they're both the same IC). If the fault appears to go away or at least changes, you know one CIA is bad. If the keyboard and joystick work then you can be fairly sure the CIA in U1 is OK.
6526 CIA chip *De-soldered and Re-mounted*
- Chip has been carefully de-soldered from a bad C64 PCB, its pins cleaned and then pressed into a new high-quality "turned-pin" type chip carrier which can be soldered directly to a PCB or pressed into a normal PCB-mounted DIL socket.
- Tested at U1 and U2 locations - working fine in both (serial, tape load, joystick and keyboard functions OK)
- Chip supplied may be a 6526, 6526A or 6526B - when used in the C64 and C64C there's no difference.
6569 R1 VIC II PAL Video Chip
- Used. Extracted from a socket - has not been soldered.
- Tested by playing various games and demos for an hour - all modes worked fine.
- The R1 VIC-II MUST be heatsinked (using the copper tab/lid of the video shielding box on an early motherboard)
Some typical faults that can occur when the VIC chip is bad include:
- Blank screen
- Graphical glitches (Especially left edge of sprites with the R1 VIC)
- Incorrect colour or none at all
6581 SID Chip (Heavy filter)
- Removed from a socket - chip has not been soldered.
- Tested with the SIDbench diagnostic program and by playing tunes from the "High Voltage SID Collection" in SIDplay for an hour.
- A heatsink is recommended to prolong life of SID chips as they run very hot (see mods section)
- Important note about the filter response on SID chips: Due to limitations in NMOS manufacturing back in the day, the filter on 6581 SIDs varies greatly from one chip to another. Sounds created for one SID can sound very different on the next (sometimes even being completely muted). This may or may not be an issue for buyers as many programs avoided using the filter due to its unreliable nature. To aid those looking for a specific type I categorize the SID Chips I sell into Light, Medium and Heavy filter types. Note that these are approximate, subjective bands - in reality, SID filters have a wide spectrum of effect strengths and the C64 motherboard can affect the filter too (eg: capacitors C10 and C11). No one SID chip will sound "ideal" on every program that uses the filters.
- The SID chips under this heading have HEAVY filters - meaning certain sounds will be more attenuated.
6581 SID Chip (Medium filter)
- Removed from a socket - chip has not been soldered.
- Tested by playing tunes from the "High Voltage SID Collection" for an hour, all played fine.
- A heatsink is recommended to prolong life of SID chips (see mods section)
- A note about the filter response on SID chips: Every SID chip is different - this was always the case due to limitations in NMOS chip manufacturing back in the day. The type of capacitors on the PCB can also have an effect. This may or may not be an issue for buyers (many programs avoided using the filter due to its unreliable nature) but to aid those looking for a specific type I categorize the SID Chips I sell into light, medium and heavy filter types. Note that these are approximate, subjective bands - in reality, SID filters have a wide spectrum of effective strengths.
- This particular chips has MEDIUM filter strength - so most effects aren't overly attenuated (EG: The main lead of the Cybernoid 2 theme is fine - on my C64 at least).
6581 SID Chip 6581R3 (MEDIUM filter response)
- An R3 version of the SID chip - it has a medium filter response - please see note below.
- Removed from a socket - chip has not been soldered. A heatsink is recommended to prolong life of SID chips (see mods section)
- Tested with SIDBENCH and by playing tunes from the "High Voltage SID Collection" for 2 hours.
- Very important note about the filter response on SID chips: Every SID chip has a different filter response profile - this has been the case since day one due to limitations of the original NMOS chip manufacturing process (the type of capacitors on the PCB can also have an effect). This may or may not be an issue for buyers (many programs avoided using the filter due to its unreliable nature) but to aid those looking for a specific type I categorize the SID Chips I sell into light, medium and heavy filter types. Note that these are approximate, subjective bands - in reality, SID filters have a wide spectrum of effective strength and the C64 motherboard can affect the filter too (eg: Capacitors C10 and C11. No one SID chip will sound "ideal" on every program that uses the filters.
7406 Logic IC
- As used at IC position U8 in the breadbin C64, and U22 in the C64C
- Common symptoms when faulty: Blank screen. Partial failure: Drive access problems, drive resets but “device not present” error when accessed.
74LS08 Logic IC
- As used at IC position U27 in the breadbin C64 and U3 in the C64C
- Common symptoms when faulty: Normal startup border but screen full (or nearly) of garbage characters.
74LS139 Logic IC
- As used at IC position U15 in the breadbin C64
- Common symptoms when faulty: Blank screen.
74LS14 Logic IC
- As used at IC position U23 in the C64C, and also in 1541 disk drive etc
74LS193 IC
- As used at IC position U30 (within the VIC-II shielded area) on earlier C64 breadbin boards.
- Brand new genuine TI parts (beware of remarked Chinese fakes - they will not work in the C64)
74LS257A/AN/P Logic IC
- As used at IC postitions U13 and U25 in the breadbin C64
- Common symptoms when faulty: Blank screen, less than 38911 bytes free at startup or “garbage” screen.
74LS258 Logic IC
- As used at IC position U14 in the breadbin C64
- Common symptoms when faulty: Blank screen.
74LS373
- As used at IC position U26 in the breadbin C64
- Common symptoms when faulty: Screen startup has normal border, but characters are scrambled.
74LS629 IC
- As used at IC position U31 in the breadbin C64 (within the VIC-II shielded area) on earlier C64 boards.
- Unused, old stock IC (not soldered) - Tested: OK
- Common issues when faulty: No video output at all, a black screen, no colour (black and white video), rolling rainbow colour patterns or white dots in both screen and border.
74LS74 Logic IC
- As used at IC position U29 (in the shielded video area) on earlier breadbins.
- Common symptoms when faulty: Entire screen blank with noise pattern, startup screen shows normal characters in multicolored "rainbow"
7805 Voltage Regulator
Replacement 5 volt regulator IC for the Spectrum, (breadbin) Commodore 64, ZX81 etc
7812 Voltage Regulator
Replacement 12 volt regulator for (breadbin) Commodore 64
8500 CPU for Commodore 64 *Desoldered*
- As used mainly in the C64C but work fine in 'Breadbin' C64's too.
- Desoldered chip with cleaned and straightened pins.
- Supplied fitted into a high quality "turned-pin" socket (acting as a piggyback carrier - these sockets have sturdy pins and can in pressed into a normal DIL socket or soldered to the PCB)
- Tested in a working PCB.
8565 R2 PAL VIC-II Chip *For C64C Only*
- Important: For C64C only (UK / European PAL version) - Not for breadbin C64.
- Extracted from a socket, has not been soldered.
- Tested: Working fine.
8580 SID Chip *For C64C Only*
- Very Important: For C64C only -This version of the SID chip is not compatible with the breadbin C64
- Extracted from a socket, has not been soldered.
- Tested with SIDBENCH, and by playing tunes from the HVSC for at least an hour - working fine.
MOS 8701 Chip from UK PAL C64C
- As found in later model breadbin C64s and the C64C near the VIC-II chip for system timing.
- Used (removed from a socket - has not been soldered.)
- Tested: Working.
901225 - 01 Character ROM for Commodore 64 (used)
Tested and removed from an IC socket - chip has not been soldered.
Typical faults that can occur with a C64 when these chips are bad include:
- Scrambled graphics in place of characters
- Glitchy Commodore font characters, especially when system is warm.
- C64 completely dead
901225 - 01 Character ROM for Commodore 64 *Desoldered*
- Has been desoldered and tested afterwards in a working boards - all bytes verfied OK.
- Supplied pressed into a high quality "turned-pin style 24 pin socket" acting as a "piggyback" chip carrier. (This means that only new, perfectly straight pins go into the existing socket on the PCB - it can of course be soldered in place if preferred).
901226 - 01 BASIC ROM for Commodore 64
Tested and removed from an IC socket - has not been soldered.
Typical faults that can occur with a C64 when these chips are bad include:
- Constant Syntax Error
- Blank screen on power up
- When return is pressed, cursor returns to home position
- Poke command doesnt work
901226 - 01 BASIC ROM for Commodore 64 * Desoldered *
- Has been desoldered and tested afterwards in a working boards - all bytes verfied OK.
- Supplied pressed into a high quality "turned-pin style 24 pin socket" acting as a "piggyback" chip carrier. (This means that only new, perfectly straight pins go into the existing socket on the PCB - it can of course be soldered in place if preferred).
901227 - 02 Kernal ROM for Commodore 64
Tested and removed from an IC socket - has not been soldered.
Some typical faults that can occur with a C64 when these chips are bad include:
- Cursor jumps back to home position
- Restore key doesnt work
- Keyboard doesnt operate when system warms up
- Blank screen on power up
- Game cartridge doesnt function
901227 - 02 Kernal ROM for Commodore 64 *Desoldered*
- Chip has been desoldered from and then tested in a working PCB - all bytes verified OK
- Supplied pressed into a high quality "turned-pin style 24 pin socket" acting as a "piggyback" chip carrier. (This means that only new, perfectly straight pins go into the existing socket on the PCB - it can of course be soldered in place if preferred).
901227 - 03 Kernal ROM for Commodore 64 (used)
- Tested and removed from an IC socket - chip has not been soldered.
- The 901227-03 can also replace the 901227-02 type (it's virtually the same code with just a couple of bug fixes)
Some typical faults that can occur with a C64 when these chips are bad include:
- Cursor jumps back to home position
- Restore key doesnt work
- Keyboard doesnt operate when system warms up
- Blank screen on power up
- Game cartridge doesnt function
901227 - 03 Kernal ROM for Commodore 64 *Desoldered*
- Has been desoldered and tested afterwards in a working boards - all bytes verfied OK.
- Supplied pressed into a high quality "turned-pin style 24 pin socket" acting as a "piggyback" chip carrier. (This means that only new, perfectly straight pins go into the existing socket on the PCB - it can of course be soldered in place if preferred).
MC4044P Phase/Frequency Detector
- As used at IC location U32 (within the VIC-II shielded area) on earlier breadbin C64 boards.
- Common symptoms when faulty: Blank screen.
- Unused, old stock parts - Tested: OK
NE556N Timer IC
- 14-pin IC used at location U20 in the breadbin C64.
- Common symptoms when faulty: Blank screen, computer will not reset or RESTORE key doesn’t work.
PLA 906114-01 Chip
- Removed from a socket - chip has not been soldered.
- Tested for at least 1 hour: OK
- A heatsink is recommended to prolong life of PLA chip if your C64 is a type without any (see mods section)
- An alternative to this chip is the PLAnkton module (scroll down).
When replacing a C64 PLA, ideally use the same version as originally fitted. Although they are all pin-compatible and perform the same job (logically) there are small timing differences which CBM accounted for in the 64's PCB. The PLA marked 251064-01 has the same characteristics as 906114-01. Other versions of the PLA are listed below when available.
251064-01 (internally, the same as 906114-01) PLA Chip
- Removed from a socket - chip has not been soldered.
- Tested for at least 1 hour: OK
- A heatsink is recommended to prolong the life of the PLA chip - the 251064-01 has a recessed core so attachment with thermal adhesive is preferable (see mods section)
- An alternative to this chip is the PLAnkton module (scroll down)
- Common symptoms when faulty: Black screen
When replacing a C64 PLA, ideally use the same version as originally fitted. Although they are all pin-compatible and perform the same job (logically) there are small timing differences which CBM accounted for in the 64's PCB. The PLA marked 251064-01 has the same characteristics as 906114-01.
82S100N PLA Chip
- Removed from a socket - has not been soldered.
- Tested: OK
When replacing a C64 PLA, ideally use the same version as originally fitted. Although they are all pin-compatible and perform the same job (logically) there are small timing differences which CBM accounted for in the 64's PCB. The 82S100N was fitted in early C64s (similar in nature to "93459 PC")
SaRuMan 64k static RAM for DRAM replacement board
- Replaces the two DRAM chips on C64 and C64c boards 250466 and 250469.
- Can also, albeit with modifications, be used to replace the RAM in C64s with 8 RAM chips - info here.
- Uses a single modern static RAM IC and only consumes around 5mA.
- Also acts as a VSP bug fixer.
- Made by Eslapion, creator of the PLAnkton.
- Note: PCB colour may vary - currently green.
TOLB Module from Eslapion - NTSC Version
A replacement for the MOS 8701 clock generator chip used on boards 250425, 250466, 250469 and the C128. Works on the C64 Reloaded too!
- Onboard oscillator makes it independent from the C64 crystal and easy to convert a C64 from PAL to NTSC and inversely
- Consumes only 9mA of power (a genuine MOS 8701 consumes 25-30mA)
Compatible with Commodore computers (with the PCB numbers stated above) carrying these video chips:
- MOS 6567 – Original NMOS version used in most C64 sold in Japan and North America
- MOS 8562 – HMOS-II version used in most C64c
- MOS 8564 – VIC-II E C128 version
300+ units sold - not a single defect and not a single compatibility problem found.
PCB colour may vary - current stock are green.
TOLB Module from Eslapion - PAL Version
As above but PAL version. Compatible with Commodore computers (with the PCB numbers stated above) carrying these video chips:
- MOS 6569 - Original NMOS PAL VIC-II (breadbin C64s)
- MOS 8565 - HMOS PAL-VIC-II (most C64Cs)
- MOS 8566 - VIC-II E PAL (C128)
PCB colour may vary - current stock are green.
|
