Set ID anyone? - UK Vintage Radio Repair and Restoration Discussion Forum

brianbelfast · 12th May 2021, 10:05 pm

This is for sale locally but I'd like to know a little about it. Thanks all.

slidertogrid · 12th May 2021, 10:31 pm

It looks like a later version of the Bush 823 with varicap tuning. 2 chip decoder which IMHO wasn't as good as the earlier single chip version.
If you do buy it check the thermistor on the power supply panel for dry joints . They used to fail, burn a hole in the panel and because it was back to back with the decoder it could splat the back of the decoder and cause a lot of damage. The flyback tuning capacitor(s?) should probably be changed and the smoothers checked before applying power.
Good luck if you do go for it!

toshiba tony · 12th May 2021, 11:09 pm

Didn't they do a presentation of the Z718 with a similar cabinet?

jayceebee · 13th May 2021, 10:13 am

It's a Murphy CV2614 fitted with the A823AV chassis, relatively reliable but not a great performer. These were flying off the shelves where I worked during the colour boom days. May have been late 73 when it was released.

I can't be sure but it looks like the door over the tuning controls is still there. It was very flimsy, often got broken and the tiny spring lost.

John.

Heatercathodeshort · 13th May 2021, 11:39 am

Without doubt the worst quality picture of the 1970s but as John says predictable and reliable. Customers never complained about the poor colour/general performance and it would have been a nightmare if they had! John.

Welsh Anorak · 13th May 2021, 1:59 pm

They certainly had a dull picture, especially nwhen viewed beside a G8, Thorn or even the Pye 697. I always found it a disappointment to fit a new tube and be greeted with a mediocre picture. The older one-chip decoder had the edge on performance. However it wasn't till the late Seventies with the Z718 then T2X series that RBM eventually had a set with a good picture. Odd, as the A640 and A816 monos were the best performers in their group.

G8vsjDave · 13th May 2021, 4:07 pm

Interesting you should say that Glyn. The 640, 816 and Z718 were all designed by the same team, The A823 being designed by another team. Before I left RBM, I built a frankenstein set for use at home, based on the A823, but with the signals panel from the A718 . The set worked well and only needed a new tripler and tube throughout it's long life.
Dave

jayceebee · 14th May 2021, 9:39 am

Funny you should mention your Frankenstein set Dave,I’ve had plans for a long time to us an A823 for some major rework. I have two identical Coop sets, one will be returned to life as originally designed and the other will have the decoder updated and the bouncy-bouncy thyristor PSU updated to possibly a switch mode design.

John.

12th May 2021, 10:05 pm	#1
brianbelfast Triode Join Date: Sep 2006 Location: Belfast, Northern Ireland, UK. Posts: 21	Set ID anyone? This is for sale locally but I'd like to know a little about it. Thanks all. Attached Thumbnails

12th May 2021, 10:31 pm	#2
slidertogrid Octode Join Date: Apr 2005 Location: Peterborough, Cambridgeshire, UK. Posts: 1,898	Re: Set ID anyone? It looks like a later version of the Bush 823 with varicap tuning. 2 chip decoder which IMHO wasn't as good as the earlier single chip version. If you do buy it check the thermistor on the power supply panel for dry joints . They used to fail, burn a hole in the panel and because it was back to back with the decoder it could splat the back of the decoder and cause a lot of damage. The flyback tuning capacitor(s?) should probably be changed and the smoothers checked before applying power. Good luck if you do go for it!

12th May 2021, 11:09 pm	#3
toshiba tony Heptode Join Date: May 2006 Location: Accrington, Lancashire, UK. Posts: 978	Re: Set ID anyone? Didn't they do a presentation of the Z718 with a similar cabinet?

13th May 2021, 10:13 am	#4
jayceebee Heptode Join Date: Jun 2007 Location: Durham, County Durham, UK. Posts: 640	Re: Set ID anyone? It's a Murphy CV2614 fitted with the A823AV chassis, relatively reliable but not a great performer. These were flying off the shelves where I worked during the colour boom days. May have been late 73 when it was released. I can't be sure but it looks like the door over the tuning controls is still there. It was very flimsy, often got broken and the tiny spring lost. John.

13th May 2021, 11:39 am	#5
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: Set ID anyone? Without doubt the worst quality picture of the 1970s but as John says predictable and reliable. Customers never complained about the poor colour/general performance and it would have been a nightmare if they had! John.

13th May 2021, 1:59 pm	#6
Welsh Anorak Dekatron Join Date: Apr 2005 Location: North Wales, UK. Posts: 6,916	Re: Set ID anyone? They certainly had a dull picture, especially nwhen viewed beside a G8, Thorn or even the Pye 697. I always found it a disappointment to fit a new tube and be greeted with a mediocre picture. The older one-chip decoder had the edge on performance. However it wasn't till the late Seventies with the Z718 then T2X series that RBM eventually had a set with a good picture. Odd, as the A640 and A816 monos were the best performers in their group. __________________ Glyn www.gdelectronics.wales

13th May 2021, 4:07 pm	#7
G8vsjDave Pentode Join Date: Jul 2010 Location: Nottingham, Nottinghamshire, UK. Posts: 229	Re: Set ID anyone? Interesting you should say that Glyn. The 640, 816 and Z718 were all designed by the same team, The A823 being designed by another team. Before I left RBM, I built a frankenstein set for use at home, based on the A823, but with the signals panel from the A718 . The set worked well and only needed a new tripler and tube throughout it's long life. Dave

14th May 2021, 9:39 am	#8
jayceebee Heptode Join Date: Jun 2007 Location: Durham, County Durham, UK. Posts: 640	Re: Set ID anyone? Funny you should mention your Frankenstein set Dave,I’ve had plans for a long time to us an A823 for some major rework. I have two identical Coop sets, one will be returned to life as originally designed and the other will have the decoder updated and the bouncy-bouncy thyristor PSU updated to possibly a switch mode design. John.