Servicing The FireBall Tuner

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This thread is a “cross- posting” article, meaning it’s a Radios-TV Blog article as well as a VRAT forum thread. What is posted on one, by way of comment or reply, appears on the other. This gives the unique opportunity for guests (non-members) to interact with forum members via the blog commenting system.
Servicing The FireBall Tuner 1 Servicing The FireBall Tuner 2 Servicing The FireBall Tuner 3 Servicing The FireBall Tuner 4 Servicing The FireBall Tuner 5

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jcdaze
jcdaze(@jcdaze)
Member
1 month ago

 

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F6D62BD8 9A68 4FE1 ADAC 8B94FCE8C6BF

A5B198EC 3195 4E72 B0C0 6566A8B4381C

I always liked the fireball tuner. I just happen to have a spare one. 

sideband
sideband(@sideband)
Member
Reply to  jcdaze
1 month ago

Posted by: @jcdaze

 

I always liked the fireball tuner. I just happen to have a spare one. 

 

I got the impression from my late older brother that these were not liked in the trade. By the time I started servicing in 1970, there were very few left so I never formed an opinion. I got on with them OK but only worked on a few.

Last edited 1 month ago by crustytv
sideband
sideband(@sideband)
Member
1 month ago

Interesting article. The KB Royal Star I have uses a fireball tuner and I’ve had to work on several of these before. The one in my set is working but there are some gain issues which are not attributed to the valves. The 6.8K was a frequent change but I wasn’t aware of the 470K resistors going high. Difficult to change those so if they are still within tolerance, they are best left alone.

irob2345
irob2345(@irob2345)
Member
1 month ago

In Australia we saw the Fireball tuner in a few Thorn Atlas TVs in the early 60’s. 6 volt valve heaters of course.
I don’t recall any real issues with them.
Admiral (US) used to have a vaguely similar tuner. Not as compact as the Fireball.
Then there was that little Pye tuner that was sourced from the UK. We saw a lot of these because they were used in the number 1 selling TV in Australia in the 60’s, the Pye Pedigree. The Pedigree was a “hero” design that saved the company. Because the channel changer knob was metal and was on the top of the TV, and because the valves were “buried” inside that tuner, the channel knob could get too hot to use! Pye released a modified knob with an insulator that fixed the problem.

jcdaze
jcdaze(@jcdaze)
Member
1 month ago

I must admit that apart from cleaning the contacts on them that I never had to do any fault finding. To clean them, once the cover was removed and the retaining nut removed it was easy to clean the sprung contacts as well as the rotating contacts whereas in a turret tuner, if it was fully loaded, meant removing enough “biscuits” in order to do the sprung contacts as well. No big deal one way or the other really though. 

PYE625
PYE625(@pye625)
Member
1 month ago

As for the cleaning solution, Electrolube is mentioned in the article but I have used Servisol super 10 (a switch cleaner and lubricant). I am presuming it is much the same thing and as long as the cleaning solution contains lubricant, I guess it is ok.

irob2345
irob2345(@irob2345)
Member
1 month ago

Cleaning tuner contacts was a frequent requirement in those days. Lazy techs would lever a side cover away with a flat-blade screwdriver and insert the tube from a spray can. Not being in that category, I would unscrew the control head, remove tuner covers(s)  and use silver polish (Silvo) in a 3 step process where the final step was a wipe of all contacts with CRC. This was a long-lasting fix.
NEVER spray contact cleaner into a tuner. It would de-tune particularly the local oscillator and frequently put the fine tuning out of range for a week or more until it dried out.
You didn’t have to fix tuners much. Any tricky faults were handled by a changeover – there were firms that specialised in tuner overhauls. The company I worked for eventually set up a bench with a test jig just to do tuners when things got quiet.
Stock faults – 820k and 1m bias resistors in RF amps, a 4.7k resistor and a 22pf cap in Astor tuners, plastic parts associated with the preset fine tuning mechanisms. Mechanical wear. Cracked soldered joints on the PCBs in Pye tuners.
Those very compact Pye tuners were not actually made by Pye UK as I recall, they were some other brand. Does anyone know?

Nuvistor
Nuvistor(@nuvistor)
Member
Reply to  irob2345
1 month ago

@irob2345 
I don’t know who made the tuners, we’re they turret or incremental? Pye up to around 1963/4 used incremental type after it was a turret of some form. The Pye 11u chassis from around 1963/64 as used in Pye, Pam, Invivta, Ekco and Ferranti brands used the turret or push button tuners.
 One type used in the Ferranti sets  was from Philips and used printed circuit ‘biscuits’ for each channel. Another push button type was used by Ekco, not sure of the make but possibly made by Pye in their Lowestoft factory.
Perhaps the tuner you refer to was made at Lowestoft , they definitely made valve UHF tuners for the group.

PYE625
PYE625(@pye625)
Member
1 month ago

I thought it was AB Metals, but could be wrong.

Nuvistor
Nuvistor(@nuvistor)
Member
Reply to  PYE625
1 month ago

@pye625 
The UK Fireball was AB metals but I thought the last sentence in irob2345s post was about a different Pye tuner. Probably I have it wrong but at least the information about the Pye/Ekco tuners is as far as I know correct.
 

PYE625
PYE625(@pye625)
Member
1 month ago

Ah yes…. I mis-read completely.

irob2345
irob2345(@irob2345)
Member
29 days ago

The earlier Pye tuners were of conventional size and shape and used switch wafers in a conventional incremental design.
The one I’m referring to was quite small – about 80 x 60 x 40mm – and used a PCB with the valves nestled into the box. It was an incremental design but used a “turret” of 3 or 4 PCB discs about 30mm diameter with contact studs around the periphery and stationary wiper contacts attached to the base PCB. It was a clever and successful design.

Nuvistor
Nuvistor(@nuvistor)
Member
Reply to  irob2345
28 days ago

@irob2345 
I didn’t see that design in the UK, though someone else may have done.

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