B251 Software

[MilanMilosevic]

Hello Revox friends,

I am looking for Revox B251 software whihc needs to be installed again to the microprocessor. Is there a link to download it somehwere or other ways to get it?
Thank you in advance.

Milan

[Frank Schieschke]

AW: B251 Software

Hi Milan,
there is nothing to program the processor.
The used type is a MAB8440 (part-nr. 1.725.720.02).
The MAB8440 is a mask-programmable type with the instruction set of the MAB8048.
If you have great luck, you have to get a MAB8400.
This version you can supply with an external EPROM, which you can plug "piggy-back" on the processor.
Looks like this one below.

But there is no software for that, except you can create your own.

[MilanMilosevic]

Re: B251 Software

Hello Frank,

thank you very much for your answer. My B251 switches on in a funny way: it turns on multiple sources at one time, does not recall previous settings etc. so I located the problem down to faulty microprocessor.

[Zeppelin]

AW: B251 Software

Hello Milan,

1.) Does the Reset work properly?
2.) Does the processor clock?
3.) Does the processor react to keyboard and/or IR comands after power-on?

The power-on configuration is stored in the 2801 EEPROM.

4.) Make sure that Pin 4 (BE Block Enable) of the EEProm is on GND.

Rgds, Ulf

[imac22]

Re: B251 Software

Hi,

I also have a B251 with uP problem.. Bought it non working, found out that someone change the uP to a Philips CD player uP, that's nice.

So shall I realize that its broken and it cant be fixed?

[eckibear]

AW: Re: B251 Software

Hi,

I also have a B251 with uP problem.. Bought it non working, found out that someone change the uP to a Philips CD player uP, that's nice.

So shall I realize that its broken and it cant be fixed?

Unless you find a 1:1 uP replacement in the universe you just bought a nice boat anchor.

[imac22]

Re: B251 Software

Thanx for the encouraging answer

I will put the amp on the long time project shelf.

[imac22]

Re: B251 Software

Maybe this could be a possible solution to extract the software from a uP!?

http://www.cpushack.com/2013/02/12/reading-mask-roms-with-python/

http://adamsblog.aperturelabs.com/2013/01/fun-with-masked-roms.html

[Zeppelin]

AW: B251 Software

It will most likely be simpler to develop a replacement uComputer and write the software from scratch... Don`t forget the MAB 8410 remote processor which is not available any longer...

[sebaki]

AW: B251 Software

A 2801 EAROM can be obtained from some (very) old Network adapters (NIC) most probably those with 16 bit ISA Bus from IBM or compatible PCs as those Cards stored their INT and ADDR info in such EAROMs

[MilanMilosevic]

Re: B251 Software

I think it is easier to get a donor B251, take the uP out of it and then use it as a door stop. :-)