The ZX Diag Cart by ByteDelight will visually show all kinds of details of your ZX Spectrum, which is both looking cool and useful at the same time!

It will make diagnosing defects a lot easier:

• Quickly check if voltages are present.
• If there is a dataline ‘stuck’
• If the M1 line is working…

The ZX Diag Cart automatically detects to which ZX Spectrum model it is connected, so it can control the ROM signals on ZX Spectrum 16/48K, 128K+, +2, +2A or +3, and many clones.

ZX Diag Cart Test and Sinclair ZX Spectrum 48k Issue 2 Repair:

I wanted to try this nice but also useful interface with my historical Sinclair ZX Spectrum 48k, not even doing it on purpose after several years of total inactivity the ZX Spectrum no longer worked.

The defect can i see is a total malfunction of the Basic interpreter with random errors and using the ZX Diag Cart i have see an error on all 16k RAM banks.

The voltage monitoring LEDs on the ZX Diag Cart show me that the -5v and the +12v are missing, consequently it was not a RAM problem but instead the transistor ZTX 650 (TR4)

Replaced the transistor it all work perfectly and passed all disgnostic test of the Diag Cart.

Gallery of the repair:

ByteDelight ZX Diag Cart Video:

Download:

• ByteDelight ZX Diag Cart Manual (1703)
• ZX Diiag Cart v2.15 +2A/+3 Fix (546)
• ZX Diag Cart Manual and Build Guide (772)

source: bytedelight.com