Advice Needed Strange Ferguson SRB1 Display. Is it an Error Code?

[retunerman]

Could anyone help me with some advice on this Ferguson SRB1 error code please?

The code (or garbage) appears the moment the receiver is powered up, there's no delay at all. All the buttons and the setup key on the rear are compeletely unresponsive and on the channel number display I get three horizontal lines (above each other) followed by the number 2 which alternates with the -- standby indicator.

I've had a look through the service manual and can find no reference to this or any other error codes, so I'm guessing it's probably kaput.

Any help would be gratefully received. I'm a newbie here and I've enjoyed reading a lot of the posts on this forum.

Many thanks

 

[philpem]

There are a couple of possible causes of the issue. There are a couple of DRAMs attached to the MAC chipset which can fail and cause a huge mess which the firmware won't be able to figure out. I think they're usually 4164s, two of them. If they're "MT" branded I'd replace them as a first step.

After that I'd check the 20.25MHz clock (which supplies the MAC section and ACM), then check voltages and other clocks, and go through the diagnostic steps for "receiver LEDs light up but does not come out of standby".

Unfortunately the system selftest status is only shown on one of the ACM diagnostic screens, which is a bit pointless because just about the whole receiver needs to be working (at least as far as output video sync and ACM comms) before it can tell you what's gone wrong ...!

 

[retunerman]

Thanks for your advice Philpem. It's a bit beyond my own technical capabilities, but I know "a man who can" and that seems like a sound logical process of investigation. Thanks very much for your time and sharing your knowledge.

 

[philpem]

No problem, please do keep us updated with how you get on. Hopefully you can get yours fixed! You've reminded me that at some point, I need to fix my Philips one. It was modified by one of the satellite vendors of the day to receive D2MAC. I think as I said above, the RAM's gone, because it behaves really strangely and won't come out of standby.

I had a Tatung which misbehaved then died completely (wouldn't come out of standby) and swapping the RAMs resurrected it.

The other potential issue on these is the DMAC chipset, I think Captain Jack (also on these forums) had one which died that way. I'll leave it for him to chime in if he likes - I can't remember the symptoms or what model of receiver it was, beyond that swapping one of the ITT D/D2MAC chips made it work again.

 

[retunerman]

It seems incredible to think these boxes are 33-34 years old now. I believe ITT was under a lot of pressure to make a working chip in time for the BSB launch. I'll keep you posted if I make any progress with the Ferguson and good luck with the Philips. They're nice looking boxes.

 

[Captain Jack]

Those DMA MAC chips are notoriously unreliable. Sometimes they fail. Sometimes they work until they get hot. Sometimes they work.

There were a few MAC decoders which were repaired by replacing either DMA chips or the VCU2133 ADC/DAC chip. They all get very hot and fail easily.

That said, none of the failures caused by the above chips stopped decoders from starting up. They just didn't decode the picture or display anything.

 

[Nipper $tring]

Wasnt that the method of setting the rf output channel on the modulator that connects to tv. If its what Im thinking of you entered a channel number between 21 to 68 eg 68 and enter. but it only worked on the remote control.

 

[retunerman]

Wasnt that the method of setting the rf output channel on the modulator that connects to tv. If its what Im thinking of you entered a channel number between 21 to 68 eg 68 and enter. but it only worked on the remote control.

Thanks for that suggestion Nipper String, I'll give that a go and report back here once I've tried it.