I bought this tiny little set from eBay this week and what a beaut set it is. Works straight out of the box. It will be recapped and a new cord . It's only 22cm across but sports 5 valves.

Photos uploaded.

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A valve a day keeps the transistor away...

I have sent a circuit diagram to be attached for your info. The output valve should be a 6K6 not a 6V6.
Hope it is of use.

Columbus Model 6 Service Bulletin

If that dial is anything to go by, it seems that the entire country only had 8 radio stations?

If that dial is anything to go by, it seems that the entire country only had 8 radio stations?

QUOTE: in 1978, New Zealand radio listeners had only five or six radio programs to choose from if they lived in a large city such as Wellington or Christchurch, all but one operated by the government controlled NZBC. Slightly better choice in Auckland where there were three private stations, worse if they lived in a small provincial town, and much worse everywhere else. (-- NZ Radio Heritage Foundation)

NZ Population 3.121 million (1978)

Sydney population ~ 3.0 million (1978)

"In 1982 [in NZ] there was a historic high of over 70 million sheep" (-- Radio NZ)

It's probably about right. There were only that many stations in Sydney at the time. 2FC, 2BL, 2GB, 2UE, 2KY, 2CH, 2UW, (2WS ~launched in 1978) and 2SM. The first two owned by the ABC and the rest commercial.

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A valve a day keeps the transistor away...

Thanks Philconut for pointing out the difference in output valves , this may be the reason its distorting now that I have recapped it. it was half recapped when I looked and it performed very well but I decided to complete the job and it now distorts . I will find a 6k6 and see if its different.

Document uploaded to Post 3.

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A valve a day keeps the transistor away...

The Columbus is only showing the YA & ZB stations located in Auckland (1), Wellington (2), Christchurch (3) & Dunedin (4).

YA stations today are NZBC's National Radio, similar to our Radio National. 2YA in Wellington, which shares the same frequency as 2BH Broken Hill, is so powerful you can pick it up over here at night.

ZB stations have been rebranded Newstalk ZB, similar to 2UE, 2GB, 3AW, etc. Newstalk ZB's morning show host until his retirement last December was Australian born Leighton Smith.

MonochromeTV
This set was built in 1946. not bad really. thats probably the reason why not many stations.

There was about 22 broadcast stations throughout NZ in 1946.

About four each in Auckland, Wellington, Christchurch & Dunedin.

Photos uploaded to Post 9.

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A valve a day keeps the transistor away...

Mmmmm. Not sure that the different output valve would cause the distortion. Check the DC voltage between grid 1 and ground of the output valve. It should be ZERO. If is positive, the coupling capacitor is faulty & that will be causing the distortion. A further check is the voltage between grid 1 and the cathode. The cathode should be a few volts (6 to 10) positive wrt grid 1.

Several notables: I would expect the plate resistor of 6Q7 to be a likely dud as well as the grid leak on the OP valve. Replacement of caps equals Wax paper types an all of the electrolytic ones. Rb's are handy for mounting on the tube socket (leave leads long: Heat). I always check the resistors as I change caps. Was this done

The tube data voltage is not particularly helpful, & neither is theirs. 6V6 is the only one that quotes 180V and the 6K6 data 100V with a 600 Ohm cathode resistor giving 7V (across it) and 6V6 180V 8.5V across Rk. The higher load may not help get it right.

6V6 normally has a 50K grid stopper: None shown. So to run it there may be a need to adjust.

Stability: One notes the absence of "G" on the valves on the schematic. Check if all of the pin 1's are grounded. The absence of shields & "G", plus the grounding of pin one says "Metal tubes" and it has but one. That could lead to instability which can cause distortion.

Do make sure all pin ones are not being used a tags of convenience.

One reason why I use an oscilloscope to calibrate is just for distortion: It then gets the job of finding where it started.