BeoGram

Re: Beogram 4000 - arm transport problem

dylan — Mon, 02 Jul 2007 02:56:08 GMT

Thanks Martin - I was thinking I'd reached the limit of expertise (which is basically looking to see if any loose wires!) - will maybe give the transistors a go but probably handover to someone with the necessary skill.

Dylan

Re: Beogram 4000 - arm transport problem

Dillen — Mon, 02 Jul 2007 01:37:37 GMT

"High" and "Low" refers to digital signal levels, 1's and 0's so to speak. The respective measured voltages will depend on the supply and the general circuit layout and may differ from one circuit to another.
An oscilloscope or data logger is required here,
especially if you need to measure and check the timing at two or more points simultaneously.

B&O's circuits may seem fairly simple at first glance but they can indeed be tricky. Servicing the electronics of a Beogram 4000 is not the easiest thing and, with all due respect, unless you feel absolutely safe I would recommend leaving servicing to someone who knows these beautiful machines and the way around their pitfalls.

Having said that, I would start by checking the transistors in the H-bridge, 8 in total I think and eventually work my way backwards.

Martin

Re: Beogram 4000 - arm transport problem

dylan — Sun, 01 Jul 2007 16:39:55 GMT

My problem is I don't really understand the queries in the troubleshooting guide - my electronics is very limited. For instance it says "FF = low" and "FO=high" - now I can find these points on the circuit board but what do high and low mean? Voltage relative to each other perhaps? What about for ones there is a single entry eg "ES low" does this mean -ve voltage compared with chassis?

Help!

Dylan

Re: Beogram 4000 - arm transport problem

Dillen — Sun, 01 Jul 2007 14:46:50 GMT

Only thing to do then is to measure about a bit and look for the fault.

Martin

Re: Beogram 4000 - arm transport problem

dylan — Sun, 01 Jul 2007 11:24:44 GMT

No unfortunately no movement at all, nor any voltage going to the motor (fine when going the other way) so I'm sure electrical.

Dylan

Re: Beogram 4000 - arm transport problem

Dillen — Sun, 01 Jul 2007 05:39:23 GMT

Does the arm servo motor spin when the arm is commanded out ? If so - replace the belt(s) and/or clean/lubricate the carriage spindle. If not - you have another fault, maybe an electronic one.

Martin

Beogram 4000 - arm transport problem

dylan — Sun, 01 Jul 2007 02:33:20 GMT

Hi all,

My BG4000 has suddenly developed a problem - the arm transport only works inwards not out, both when reaching end of record or pressing the > have no effect. I have minimal electronics skills and a multimeter but looking at the troubleshooting flowchart I get flummoxed. Have checked that adjusting IVR6 makes no difference but beyond that get stuck. Getting completely out of my depth! what I'm hoping is that some wise man will say "don't worry this often happens just replace all the capacitors" (which I think I could manage).

thanks in advance

Dylan