Replacement Components

Many components used in the Sinclair hardware, peripherals, etc. are no longer manufactured. However for most of these components there are modern alternatives. Much research was conducted by DEATH and others on the World of Spectrum forums

ZX Spectrum 48k

All versions

• ZTX213 can be replaced with BC251, BC307, BC512, BC557
• ZTX313 can be replaced with BC172, BC183, BC238, BC383
• ZTX650 can be replaced with BC537, BC737, BC487, BC489, BC538 (using BC487 in TR4 position may cause overheating)
• BC184 can be replaced with BC384, BC413, BC550

For issue 2 boards and above

• ZTX650 can be replaced with ZTX651 in TR4 position
• ZTX213 can be replaced with ZTX750 in TR5 position
• ZTX313 can be replaced with BC547, BC548 and BC549 in TR1/TR2 position (Usually improves picture quality significantly)
• BA157 can be replaced by BA158 or 1N4937 fast recovery diodes

For issue 3 boards and above

• ZTX450 can be replaced with ZTX650/651 in TR7 position
• ZTX313 can be replaced with BC184 in TR8 - TR9 position

Issue 3B

• TR1, TR2, TR3 and TR6 can be replaced with MPS2369

Issue 6A

• TR8 and TR9 can be replaced with BC549B

Spectrum +3

• TR1 in the +3 PSU is an H1061. Possible alternatives include the BD243C and TIP41C

Integrated Circuits

RAM

• MM5920N (national Semiconductors) chips are equivalent to 4116 RAM chips
• AM9016EDC (AMD) chips are the same as 4116 chips.
• IMS2600P-12 (Inmos) chips work in any upper RAM position (IC15-22)
• 41256 chips work in place of 4164 upper RAM chips
• V53C256P80L chips work in any upper RAM position (IC15-22)
• MN41257-12 chips work in any upper RAM position (IC15-22)

Logic

• 74LSxx series chips can be replaced with 74HCTxx series chips

CPU

Various makes of Z80 processor are used on Spectrums. Zilog Z80 CPU NEC D780C

Suppliers

Companies who supply suitable components

• Cricklewood Electronics specialise in hard to find/obsolete components.
• Rapid Electronics
• Farnell Large supplier with a huge product range.