Bush TV176 dropper replacement and lack of height - UK Vintage Radio Repair and Restoration Discussion Forum

Sean Williams · 1st Aug 2006, 3:33 pm

I now have this set from Jim B, and would find some service info useful....

Anyone got anything? Looks like the dropper is o/c, so there is one place to start.....

Cheers
Sean

Sean Williams · 2nd Aug 2006, 1:55 pm

A picture of progress so far.......

Working on 625, with a foot of wire as an antenna - 405 seems to work too

Still need a dropper, and some circuit info.......

Cheers
Sean

tvden · 2nd Aug 2006, 5:52 pm

Sean
I doubt if you will get a NOS dropper - I could be wrong, can't you just bridge the old one with w/w ceramics?

Sean Williams · 2nd Aug 2006, 6:16 pm

Hi Den,

Yep, I could do that, but I would rather use the original part if possible - after all, the set is under 30 years old!

If nothing is forthcoming, then I will make a subchassis with some aluminium clad resistors fitted - that way the repair is reverseable

Cheers
Sean

jim_beacon · 2nd Aug 2006, 6:34 pm

Glad to see you got it going! Sorry about the standards switch - I hadn't looked

Jim.

Sean Williams · 2nd Aug 2006, 10:54 pm

Hi Jim,

Standards switch is no problem - was just bodged up with locking wire......

Now, the tuner, well, that might be a different story.......

Looks like the phantom has been playing with the pushbutton selector, as only four of them work properly - I am really looking forward to having a look at what has happened in there.

Cheers
Sean

Hybrid tellies · 3rd Aug 2006, 12:06 am

Great to see that you have got this set working, picture does look rather good. I loved working on these sets, they were definitely the best of the bunch of the last generation dual standard mono sets.

The main problem with these and other RBM mono sets was the line output transformer, where the EHT overwind would go shorted turns. Other than that most faults were and are easily clearable. The integrated tuner was built like a tank and so was very reliable, the plastic buttons would wear down on the inside making it difficult to change channel.

Sean Williams · 30th Aug 2006, 6:01 pm

Ok, an update......

Fitted Glyn's last NOS dropper - A charming shade of blue!

However, is it usual for the new dropper to smoke for a while after fitting?

I have metered the AC current drawn by the heater chain - Approx 250ma, and the total AC current drawn by the set is around 640ma - this closely matches the set's rating of 165 watts..

I am still a little concerned by the amount of heat this dropper is lobbing out!

I have checked most of the caps fitted to the set, and they seem quite happy, I have changed a couple of poor ones in the line TB area....

Cheers
Sean

Steve_P · 30th Aug 2006, 6:07 pm

Is the whole thing smoking or just one part?

Cheers,

Steve P

Sean Williams · 30th Aug 2006, 6:24 pm

Hi Steve,

Looks like the whole dropper......

Cheers
Sean

jay_oldstuff · 30th Aug 2006, 7:25 pm

I wouldn't be too concerned about the whole of the dropper smoking a little.
When I changed the dropper in my RGD, the new dropper smoked for about half an hour while all the crud from my fingers burnt off.

Jay

Heatercathodeshort · 30th Aug 2006, 8:30 pm

Hello,
This set is fitted with the RBM 640 chassis, one of the best. The 6 button integrated tuner has incredible stability and rest.
The tuner system operation is controlled by 'keyplates' slotted in the front of the unit under the pushbuttons. They can be set for 'band one 405' UHF 625' band 3 405' or any combination! I sold a huge number of these sets when new and my only complaint was the row of buttons on the back.
Customers used to twiddle these and get in a hopeless mess. I used to set the whole lot up then mark the tops of the controls with a Tippex dot. When all dots were in line the set would be about right.....Great sets and a cracking picture.
Regards John.

Steve_P · 30th Aug 2006, 9:03 pm

Lack of Height: Check R336 and R337 before you change V36 (PCL85/PCL805).

Cheers,

Steve P

Sean Williams · 30th Aug 2006, 10:07 pm

Hi Richard,

Yep, HMP solder and good Mechanical joints - The smoke is much reduced after about 40 mins of running.

Steve P - Glad you mentioned those resistors - I was just going to nip to the valve store to slip a new PCL805 in.....

Will report back later in the week, other stuff to do now.....

Cheers
Sean

1st Aug 2006, 3:33 pm	#1
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,518	Bush TV176 dropper replacement and lack of height I now have this set from Jim B, and would find some service info useful.... Anyone got anything? Looks like the dropper is o/c, so there is one place to start..... Cheers Sean __________________ Engineers make things work and have spare bits when finished

2nd Aug 2006, 1:55 pm	#2
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,518	Re: Bush TV176 A picture of progress so far....... Working on 625, with a foot of wire as an antenna - 405 seems to work too Still need a dropper, and some circuit info....... Cheers Sean Attached Thumbnails __________________ Engineers make things work and have spare bits when finished

2nd Aug 2006, 5:52 pm	#3
tvden Retired Dormant Member Join Date: Oct 2003 Location: Halesworth, Suffolk, UK. Posts: 413	Re: Bush TV176 Sean I doubt if you will get a NOS dropper - I could be wrong, can't you just bridge the old one with w/w ceramics?

2nd Aug 2006, 6:16 pm	#4
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,518	Re: Bush TV176 Hi Den, Yep, I could do that, but I would rather use the original part if possible - after all, the set is under 30 years old! If nothing is forthcoming, then I will make a subchassis with some aluminium clad resistors fitted - that way the repair is reverseable Cheers Sean __________________ Engineers make things work and have spare bits when finished

2nd Aug 2006, 6:34 pm	#5
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: Bush TV176 Glad to see you got it going! Sorry about the standards switch - I hadn't looked Jim.

2nd Aug 2006, 10:54 pm	#6
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,518	Re: Bush TV176 Hi Jim, Standards switch is no problem - was just bodged up with locking wire...... Now, the tuner, well, that might be a different story....... Looks like the phantom has been playing with the pushbutton selector, as only four of them work properly - I am really looking forward to having a look at what has happened in there. Cheers Sean __________________ Engineers make things work and have spare bits when finished

3rd Aug 2006, 12:06 am	#7
Hybrid tellies Nonode Join Date: Jan 2004 Location: 1966-1976 Coverack in Cornwall and Helston Cornwall. 1976-present Bristol/Bath area. Posts: 2,967	Re: Bush TV176 Great to see that you have got this set working, picture does look rather good. I loved working on these sets, they were definitely the best of the bunch of the last generation dual standard mono sets. The main problem with these and other RBM mono sets was the line output transformer, where the EHT overwind would go shorted turns. Other than that most faults were and are easily clearable. The integrated tuner was built like a tank and so was very reliable, the plastic buttons would wear down on the inside making it difficult to change channel. __________________ Simon BVWS member

30th Aug 2006, 6:01 pm	#8
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,518	Re: Bush TV176 Ok, an update...... Fitted Glyn's last NOS dropper - A charming shade of blue! However, is it usual for the new dropper to smoke for a while after fitting? I have metered the AC current drawn by the heater chain - Approx 250ma, and the total AC current drawn by the set is around 640ma - this closely matches the set's rating of 165 watts.. I am still a little concerned by the amount of heat this dropper is lobbing out! I have checked most of the caps fitted to the set, and they seem quite happy, I have changed a couple of poor ones in the line TB area.... Cheers Sean __________________ Engineers make things work and have spare bits when finished

30th Aug 2006, 6:07 pm	#9
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Bush TV176 Is the whole thing smoking or just one part? Cheers, Steve P __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

30th Aug 2006, 6:24 pm	#10
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,518	Re: Bush TV176 Hi Steve, Looks like the whole dropper...... Cheers Sean __________________ Engineers make things work and have spare bits when finished

30th Aug 2006, 7:25 pm	#11
jay_oldstuff Octode Join Date: Jan 2005 Location: Hyde, Greater Manchester, UK. Posts: 1,074	Re: Bush TV176 I wouldn't be too concerned about the whole of the dropper smoking a little. When I changed the dropper in my RGD, the new dropper smoked for about half an hour while all the crud from my fingers burnt off. Jay __________________ The light at the end of the tunnel is probably the headlight of an oncoming train

30th Aug 2006, 8:30 pm	#12
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: Bush TV176 Hello, This set is fitted with the RBM 640 chassis, one of the best. The 6 button integrated tuner has incredible stability and rest. The tuner system operation is controlled by 'keyplates' slotted in the front of the unit under the pushbuttons. They can be set for 'band one 405' UHF 625' band 3 405' or any combination! I sold a huge number of these sets when new and my only complaint was the row of buttons on the back. Customers used to twiddle these and get in a hopeless mess. I used to set the whole lot up then mark the tops of the controls with a Tippex dot. When all dots were in line the set would be about right.....Great sets and a cracking picture. Regards John.

30th Aug 2006, 9:03 pm	#13
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Bush TV176 Lack of Height: Check R336 and R337 before you change V36 (PCL85/PCL805). Cheers, Steve P __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

30th Aug 2006, 10:07 pm	#14
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,518	Re: Bush TV176 Hi Richard, Yep, HMP solder and good Mechanical joints - The smoke is much reduced after about 40 mins of running. Steve P - Glad you mentioned those resistors - I was just going to nip to the valve store to slip a new PCL805 in..... Will report back later in the week, other stuff to do now..... Cheers Sean __________________ Engineers make things work and have spare bits when finished