B&O Beomaster 8000 brain transplant

[Studio263]

Originally Posted by jjl

I suspect that your set used an EAROM such as the ER1400

Very nearly, the actual chip is a TI TMS3529 but it looks very similar to the ER1400 in the way it works. I didn't realise that battery backed RAM was not practical when this set was designed. I'm sure I seen Grundig TV sets with a little drawer in the back with 4 AA cells inside that pre-date the Beomaster 8000, but then Grundig always did have odd ideas about this sort of thing.

Some improvements have been made to the software in the light of a few weeks of use:

1) The remote control routine now makes use of the fact that the transmitter sends each code twice. The software now stores the first code and only responds to the instruction if the next one received is the same. This has cured a few odd cases of spurious operation (e.g. very occaisionally changing to FM preset P4 when the balance control is used ).

2) The FM frequency display now only shows the received frequency in "auto" mode when the tuning reaches the correct point and the AFT has locked on. This avoids a "fruit machine" type display when changing from one present programme to another which is at the opposite end of the band (fun though that was!).

3) In "auto" tuning mode the AFT is now cancelled for 0.5s as soon as the tuning is altered by one increment or more. This makes it easier to "tune away" from a station, previously it was necessary to overcome the AFT by building up a large enough tuning error to escape the pull-in range, causing the "station OK" line to clear and therefore telling to software to cancel the AFT. If the control is disturbed by accident the error is small enough for the AFT to pull the tuning back after the 0.5s delay elapses.

All good fun, I am planning to make the software availalbe on two pre-programmed ICs for repair purposes early next year.

[bobbyball]

I'm just sorry I didn't pick up one of those systems a few years ago when they could be had for beans. Especially as I now know a "nice man" who can fix them!

[Studio263]

Originally Posted by bobbyball

I'm just sorry I didn't pick up one of those systems a few years ago when they could be had for beans.

Still good value at the current asking prices, nothing else (old or new) comes anywhere close in terms of performance and operational refinement. You are right though; it was more fun when they were free.

As regards the change I've made to the FM display in "auto" mode, I should have pointed out that the display shows the "target" frequency until the AFT has locked (as it does all the time in "manual" mode) rather than being blanked as my initial description suggests. This mirrors closely what the original software does, which was the aim of the change.

[chartz2]

Hi Tim,

I too am impressed.
Are you contemplating selling those then, along with instructions?
I am now keeping a second tatty - and with many segments missing - but working Beomaster 8000 for parts! But your work is indeed reassuring for the future. These will work forever!

Jacques

[Gillian]

Wow, just Wow. Mere words just seen pure artifice to the extent of your skills!
You are indeed right as to the unfolding nature of future restorations.

These skills are needed in musical instruments too, like the Sequential Circuits Prophet 5 etc that use outdated microcontrollers and uv erasable eeproms and are now worth 4 figure sums.

My skills seem minor in comparison, hats off to you, I'll get me coat!!

Gill