Search results

I am sharing some images forom U8B pins: PIN 1 U8B: PIN 2 U8B: PIN 3 U8B: PIN 4 U8B: PIN 5 U8B: PIN 6 U8B: PIN 7 U8B: PIN 8 U8B: PIN 9 U8B: PIN10 U8B: PIN 11 U8B: PIN 12 U8B: PIN 13 U8B: PIN 14 U8B: PIN 15 U8B: PIN 16 U8B:

Thank you stepleton. Yes I tested 3 x 74F283 (U8B,U9B,U10B) only on IC tester. Do you think they may be faulty? I am attaching below measurements from A1(UA1) - A8 (UA8) on CPU. RESET PIN 18 on CPU (CH1) and PIN 29 UA1 (CH2) on CPU: RESET PIN 18 on CPU (CH1) and PIN 30 UA2 (CH2) on CPU...

I have one interesting find. I removed both ROMs from working and non working CPU board. I compared CPU signals on pins of both CPU boards when power on. They look simmillar. So I thought it must be something with ROM sockets? (ROM chips are tested and working fine. I have measured with...

Thanks. I am pasting schematics and pins measurements. I am pasting images from scope Pins from ROM and from CPU: RESET PIN 18 on CPU (CH1) and PIN 2 UA13 (CH2) on 341-0175 and PIN 2 (CH2) 341-0175 ROM: RESET PIN 18 on CPU (CH1) and PIN 43 UA15 (CH2) on CPU: RESET PIN 18 on CPU (CH1) and...

Can CPU trigger reset signal by himselves because something else is wrong (error)? Assuming 7417 is ok and from the schematics and measurements it looks that CPU trigger reset signal.

Hi Stepleton, Thank you for quick reply and advices. Regarding your questions: 1. I am pasting of an image of \RESET pin 18 on CPU after Reset button push on Lisa motherboard. Pin 18 is CH1 2. Yes, \RESET behaviour look the same if only the CPU board and no other boards are plugged in. The...

Hello Colleagues. I found this interesting simmilar thread (here ) and I have the same problem as BEU, but unfortunately I don't get error 41. I still have the same symptom of flickering black and white squares on the CRT with only the CPU board inserted like BEU had on the beginning of his...

Hi, Thanks for kick answer. Yes I will start a new thread. Yes. CPU works, both ROM's, VSROM and SRAMs too.

Hello Colleagues. I found this interesting thread and I have the same problem as BEU, but unfortunately I don't get error 41. I still have the same symptom of flickering black and white squares on the CRT with only the CPU board inserted like BEU had on the beginning of this thread. I know that...

Hi friends, Is it possible to burn VSROM with the valid serial number that is on the LISA sticker? I had to swap VSROM because it failed, so I would like to have original. My Lisa Office System software has also previous serial written to it, so I would like to be able to run nit or...

Hi, Did you managed to solve error 82 in your widget? I have the same so I need to figure out what's happening.

hello Gentelmens, I am receiving #71 (parity error) and my Lisa cannot boot successfully. I put only non-working 512k memory into Lisa. This is my result from Service Mode test: Does anyone is familiar what might be wrong with this memory board? I appreciate any help. Thanks