I thank my dear friend for the donation of the motherboards.
A dear friend sent to me a few things to repair or test, i will see to do my best.
Things to repair/testing:
Things for spare parts or to keep:
Replaced a old yellowed Amiga 1200 keyboard with a new one.
I have made some works for a friend and i didn’t want money, the friend then wanted to contribute to my Electronic Lab with this Hot Air Desoldering Station. Thanks, i appreciate it.
Video demostration:
source: aoyue.com
I have repaired an Commodore VC-1541 Floppy Drive donated by Alessio. The Floppy Drive doesn’t take any commands via IEC.
The components that have been replaced are:
Material donated:
Thanks Alessio for the donation.
I had several problems with the repair of the Hewlett-Packard HP-85.
The first problem was the way to reconstruct the pinch roller using a latex tube, this is a very bad choice, then i have used a 10mm heat shrink, this choice instead is very good.
The second problem was the rubber parts of the pinch roller are literally dissolved and the rubber is went to cover the optical diode and part of the pcb and of course nothing has worked and the tape drive was always in stalled state.
After cleaning, the drive started to work perfectly. The last problem are the magnetic tapes 3M DC-1000 instead of HP DC-100, for the correct operation you must perform a modification by adding a resistor of 2kohm in parallel to the already present on the pcb. After this mod you need to format the tape with the “erasetape” command.
I must also thank John of the site vintagecomputers.freeserve.co.uk for the support.
Download:
source: voidware.com/calcs/hp85rep hp9845.net vintagecomputers.freeserve.co.uk
Replacement:
Simple steps to replace the keyboard Membrane of the Sinclair ZX81. The removal of the old keyboard is not illustrated but it is a very easy job.
source: rwapsoftware.co.uk
I have repaired an motherboard of a Commodore CBM 4008 for a friend. The computer at the start-up shows only a black screen
The components that have been replaced are:
The computer after the repair works perfectly. You can see from the Photo.
I have repaired an Enterprise 64 (SixtyFour) for a friend. The defect via Composite or RF was a Black Screen but with the RGB output you could see a video signals without vertical sync.
The components that have been replaced are:
The computer after the repair works perfectly. You can see from the Photo.
Download: Enterprise 64/128 Schematics (1181)
source: enterprise.iko.hu
Console Amstrad GX4000 Repaired.
The fault is was caused by a wrong power connection. It was ‘resting’ the power plug of 11v on the power plug of 5v (monitor input).
Replaced parts:
The components have been recovered from the Amstrad 464+
TI-99/4A MBX Expansion System Repaired.
The interface MBX Expansion System was dead and the power voltage was in short-circuited. The failure was caused by the filter between the power supply and the 7805.
Video:
A few things to repair for a friend.
Defect: unknown.
I have repaired an Atari 800XL for a friend. The failure was caused by a faulty cpu, the computer freezes after 10 minutes of operation, using an oscilloscope i have noticed that the clock pin of the cpu did not give me more signal but when i have used the synthetic ice spray on the cpu has resumed to work.
This type of cpu (Atari customized 6502 – C014806-12 Sally) is not easy to find but fortunately a friend of mine (Carlo) has found a spare part for me.
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