Roberts R200 "Trader" 1449 Service Sheet - UK Vintage Radio Repair and Restoration Discussion Forum

steve1811uk · 24th Mar 2006, 9:50 am

Hi, Just been working on my Roberts R200 (Early Version) and found that there is a mistake on the service sheet. There is a discrepancy between the schematic and the PCB drawing, R12 and R13 are in fact swapped. Hope this helps someone. A second opinion is welcomed. Steve.

Darren-UK · 24th Mar 2006, 2:26 pm

Hi Steve,

I can't see any problem here, in the early version of the R200 both these resistors are of the same value anyway. I take it you're using Trader 1449 ?

steve1811uk · 24th Mar 2006, 3:18 pm

I know they are the same value 560 ohm but I found that TR4 emitter resistor (marked as R13 on the schematic) is actually in the position shown as R12 on the PCB layout.

The power supply decoupling resistor (marked as R12 on the schematic) is actually in the position shown as R13 on the PCB layout.

I hoped that this would prove useful information.

I spent approx 30 minutes trying to work out why I couldn't see an expected voltage of approx -8 volts at the junction of R12 / R10. What I'd actually been doing was measuring the voltage at TR4 emitter.

Steve

radiohm · 24th Mar 2006, 11:31 pm

Hi Steve,
when i first read the thread i thought the same as Darren, why bother-no difference.

But when you put it like that i think it is worth making a note of, when looking for voltages, etc.

Regards.

Mike.

Darren-UK · 25th Mar 2006, 12:33 am

Ah yes, right, I'm with you now

Generally speaking, Trader sheets are not renowned for 100% accuracy and one famous blunder, as I recall, concerns the Bush VHF61 ..... but that's going OT.

24th Mar 2006, 9:50 am	#1
steve1811uk Retired Dormant Member Join Date: Mar 2006 Location: Manchester Posts: 33	Roberts R200 "Trader" 1449 Service Sheet Hi, Just been working on my Roberts R200 (Early Version) and found that there is a mistake on the service sheet. There is a discrepancy between the schematic and the PCB drawing, R12 and R13 are in fact swapped. Hope this helps someone. A second opinion is welcomed. Steve.

24th Mar 2006, 2:26 pm	#2
Darren-UK Retired Dormant Member Join Date: Apr 2003 Location: Blackpool, Lancashire, UK. Posts: 4,061	Re: Roberts R200 "Trader" 1449 Service Sheet Hi Steve, I can't see any problem here, in the early version of the R200 both these resistors are of the same value anyway. I take it you're using Trader 1449 ?

24th Mar 2006, 3:18 pm	#3
steve1811uk Retired Dormant Member Join Date: Mar 2006 Location: Manchester Posts: 33	Re: Roberts R200 "Trader" 1449 Service Sheet I know they are the same value 560 ohm but I found that TR4 emitter resistor (marked as R13 on the schematic) is actually in the position shown as R12 on the PCB layout. The power supply decoupling resistor (marked as R12 on the schematic) is actually in the position shown as R13 on the PCB layout. I hoped that this would prove useful information. I spent approx 30 minutes trying to work out why I couldn't see an expected voltage of approx -8 volts at the junction of R12 / R10. What I'd actually been doing was measuring the voltage at TR4 emitter. Steve

24th Mar 2006, 11:31 pm	#4
radiohm Pentode Join Date: Jan 2006 Location: Stockton On Tees, Cleveland Posts: 18	Re: Roberts R200 "Trader" 1449 Service Sheet Hi Steve, when i first read the thread i thought the same as Darren, why bother-no difference. But when you put it like that i think it is worth making a note of, when looking for voltages, etc. Regards. Mike.

25th Mar 2006, 12:33 am	#5
Darren-UK Retired Dormant Member Join Date: Apr 2003 Location: Blackpool, Lancashire, UK. Posts: 4,061	Re: Roberts R200 "Trader" 1449 Service Sheet Ah yes, right, I'm with you now Generally speaking, Trader sheets are not renowned for 100% accuracy and one famous blunder, as I recall, concerns the Bush VHF61 ..... but that's going OT.