Thurlby LA4800 POST problems

[Electron_Foton]

I have just bought a second hand Thurlby LA4800 logic analyzer without any
documentation. Yesterday I was running some tests and all seem to work fine.
While in one off the menus, my screen started to flicker ,and all display
items
where gone. I rebooted the analyzer and it stoped on the POST with the
message: no disassembler pod found. I connected the disassembler pod and
restarted the analyzer, but it came back with the same error. I took off the
case hood and disconnected the controller board. It has a firmware EPROM chip,
a
UART chip, 3 memory chips and a Hitachi microprocessor on it. Also there is a
battery on it, and I
guess it used for retaining the user settings on the memory chips or the
memory on the microcontroller. So I took out the memory chips and let them
sit for a while and them connected them
back on the board hoping the system would boot normaly again: sadly It came
up with
the same error message. Next step was to disconect the battery, so I did:
still no result. I'm stuck right now and in desperate need for some help...

Can anyone help me with this problem?

Regards,
E_F

 

[Mike Harrison]

I have just bought a second hand Thurlby LA4800 logic analyzer without any
documentation. Yesterday I was running some tests and all seem to work fine.
While in one off the menus, my screen started to flicker ,and all display
items
where gone. I rebooted the analyzer and it stoped on the POST with the
message: no disassembler pod found. I connected the disassembler pod and
restarted the analyzer, but it came back with the same error. I took off the
case hood and disconnected the controller board. It has a firmware EPROM chip,
a
UART chip, 3 memory chips and a Hitachi microprocessor on it. Also there is a
battery on it, and I
guess it used for retaining the user settings on the memory chips or the
memory on the microcontroller. So I took out the memory chips and let them
sit for a while and them connected them
back on the board hoping the system would boot normaly again: sadly It came
up with
the same error message. Next step was to disconect the battery, so I did:
still no result. I'm stuck right now and in desperate need for some help...

Can anyone help me with this problem?

Regards,
E_F

Try calling Thurlby-Thandar - IME they can be very helpful. They also do service manuals for most
of their products ( proper ones, with schematics).

 

[Alison]

Can anyone help me with this problem?

Regards,
E_F

Mmmm. I have a 4800 here. It doesn't need any pods connected at all to get
to the main menu.

I'll just have a look at the service manual... Not alot..

The service manaul doesn't tell you anything like, take measurement from
this point it should be high.. It's not like the oscilloscope repair
service manuals.

The 3200/4800 are pretty good straight forward analysers though, and
relatively cheap when you can find one. But TT are very helpful, I'll give
them that.