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 Post subject: NZ MADE "PACEMAKER" 1957 Transistor Radio
PostPosted: Jan Sat 18, 2020 2:06 am 
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Joined: Jan Thu 16, 2020 12:29 am
Posts: 292
I though I would post this link to an interesting transistor radio I restored. It would probably be a very uncommon radio in the USA, but still quite a few in NZ where they were made. It is an interesting one, especially to come out of a small country like NZ in 1957 and it may well be one of the World's first MW band transistor radios to incorporate an RF stage.

With this radio, as many vintage transistor types, the tuning knob had clouded over. So I machined out the flat clear window of if, kept the central part and the perimeter of it and replaced it with a disc machined out of fresh acrylic sheet. So that is a technique that can basically save most of the knob and solve the problem.

The radio has an outward appearance similar to a Sony TR-72, but was hand wired and unlike the TR-72 did not incorporate a pcb:

http://worldphaco.com/uploads/THE_PACEM ... M_1957.pdf


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Pacemaker.jpg
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 Post subject: Re: NZ MADE "PACEMAKER" 1957 Transistor Radio
PostPosted: Jan Sat 18, 2020 3:18 am 
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That's a beautiful radio.


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 Post subject: Re: NZ MADE "PACEMAKER" 1957 Transistor Radio
PostPosted: Jan Sat 18, 2020 3:40 am 
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Joined: Oct Mon 26, 2009 10:02 pm
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Location: Indianapolis, IN
Very neat radio !

I've read about these somewhere on-line and was impressed that they contain a tuned RF-amp stage, but noticed in your article that they contain only one IF amplifier. Thanks for link to your document---have saved it for future reference...

Also interesting about your repair for the cloudy knobs. I typically clean then polish knobs that have what I call "acetate fungus" using Novus-2, but have noticed it is returning on some in collection. Read recently on-line that it is caused by surface exuding plasticizer---maybe not properly heat-stabilized during manufacture ? Just wonder how involved that process is and if older parts can be stabilized again once residue removed...

John


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 Post subject: Re: NZ MADE "PACEMAKER" 1957 Transistor Radio
PostPosted: Jan Sat 18, 2020 10:41 am 
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Joined: Jan Thu 16, 2020 12:29 am
Posts: 292
xrhonda91 wrote:
Very neat radio !


Also interesting about your repair for the cloudy knobs. I typically clean then polish knobs that have what I call "acetate fungus" using Novus-2, but have noticed it is returning on some in collection. Read recently on-line that it is caused by surface exuding plasticizer---maybe not properly heat-stabilized during manufacture ? Just wonder how involved that process is and if older parts can be stabilized again once residue removed...

John


With this particular knob, the plastic had become cloudy all of the way through its thickness.

Prior to repairing it the way I did, I tried the three grades of Novus polish, but it did not help.

The Novus polish I find is great though, if the problem is just on the surface of the plastic.

You can see from the photo how the perimeter of the knob still has a cloudy slightly yellowish look to it.


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 Post subject: Re: NZ MADE "PACEMAKER" 1957 Transistor Radio
PostPosted: Jan Sat 18, 2020 5:34 pm 
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Joined: Mar Sun 15, 2015 2:02 am
Posts: 109
I have two pacemakers and they both have clouded plastic lenses. Great performers though.

I can attest to polishing and polishing and the yellow still remains.

Even tried the retrobrite approach to see if the yellowing was Boron. It is not :)

How did you manage to hold the dial to machine it as it's kind of stubbly ?

I would love to give the replacement a try on one of them.


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 Post subject: Re: NZ MADE "PACEMAKER" 1957 Transistor Radio
PostPosted: Jan Sat 18, 2020 8:35 pm 
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Location: Ashhurst, New Zealand
Very nice Pacemaker and a great restoration - some appear on our auction site looking like the they had been kept out in the chicken shed...

Interesting article here...

https://www.vintageradio.co.nz/model/pa ... ansistor-8

....which also shows a pic of the chassis and a schematic. I have a curiosity - an Ultimate "Transistor 8" that appears to show a similar set of components but not the layout.....

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DSC_0317 sml.jpg
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...which was made in NZ by "Ultimate-Ekco" around 1959.

However I also have a mystery - an Ekco radio in a different case but the same chassis and components.....

Attachment:
DSC_1592 cropped 4-3.jpg
DSC_1592 cropped 4-3.jpg [ 783.56 KiB | Viewed 1109 times ]


...that was probably a prototype for NZ production. Both radios perform very well but need careful neutralisation to stop oscillation and get the best gain.

_________________
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 Post subject: Re: NZ MADE "PACEMAKER" 1957 Transistor Radio
PostPosted: Jan Sat 18, 2020 10:46 pm 
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majoco wrote:


Yes especially the schematic. When I restored the radio I had no access to the schematic, so I traced it out by hand (It is always a wise move) . The radio, soldering and parts looked entirely original. And, in the audio amp section, I came across an unusual method, where both AC & DC negative feedback was acquired from the PRIMARY of the audio opt transformer, via a 270k resistor to the driver transistor I labelled X5. It relies on the small DC resistance of the primary to work for DC stabilisation. It must have been one of the company's design iterations.

But as seen on the MFR's schematic, or that version of it at least, they take it from the emitter of the output transistors to the emitter of Q5, the pre-driver transistor, which is more conventional. And they have NFB from the voice coil.


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PM3.jpg
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 Post subject: Re: NZ MADE "PACEMAKER" 1957 Transistor Radio
PostPosted: Jan Sat 18, 2020 11:01 pm 
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Joined: Jan Thu 16, 2020 12:29 am
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shaunp wrote:

How did you manage to hold the dial to machine it as it's kind of stubbly ?



As I recall I held the inside edge of it by reversing the three jaws of the three jaw chuck and having them expand outwards to grip it. Also I supported its perimeter with some tape and a sleeve to prevent it expanding. I would not call it an easy job, but if done correctly it works very well. Also I used a very small amount of 24hr expoxy resin to fit the new disc, making a near invisible join, not acrylic glue because it has variable reactions with old plastics.


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 Post subject: Re: NZ MADE "PACEMAKER" 1957 Transistor Radio
PostPosted: Jan Sun 19, 2020 1:40 am 
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Joined: Aug Sat 16, 2014 2:19 am
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Location: Palos Verdes, CA
Ever since I read about the Pacemaker on James Butters' website, I've looked for one for sale on eBay, but have never seen one listed:

https://www.jamesbutters.com/pacemakertransportable.htm

I do have a Sony TR-72 transistor radio, which can be difficult to find as most of the radios for sale are from Canada. Thanks for sharing! - Mark


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 Post subject: Re: NZ MADE "PACEMAKER" 1957 Transistor Radio
PostPosted: Jan Sun 19, 2020 3:46 am 
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I'll keep an eye open for one/any on our auction site - or you could do the same.....you don't have to join/log in to browse.....

https://www.trademe.co.nz/

_________________
Cheers - Martin ZL2MC


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 Post subject: Re: NZ MADE "PACEMAKER" 1957 Transistor Radio
PostPosted: Jan Sun 19, 2020 7:07 pm 
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majoco - Thank you for the link to trademe.co.nz! - Mark


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 Post subject: Re: NZ MADE "PACEMAKER" 1957 Transistor Radio
PostPosted: Jan Mon 20, 2020 12:37 am 
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That is a beautiful radio.


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 Post subject: Re: NZ MADE "PACEMAKER" 1957 Transistor Radio
PostPosted: Jan Sun 26, 2020 4:07 am 
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Here's one...

https://www.trademe.co.nz/electronics-p ... 2106f0-004

Not quite as sharp as the OP's, but still looks very nice - the early wooden cases seemed to have survived much better than the later leatherette covered versions.

$25 NZ - can't go wrong!

_________________
Cheers - Martin ZL2MC


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 Post subject: Re: NZ MADE "PACEMAKER" 1957 Transistor Radio
PostPosted: Jan Sun 26, 2020 1:17 pm 
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majoco wrote:
Here's one...

https://www.trademe.co.nz/electronics-p ... 2106f0-004

Not quite as sharp as the OP's, but still looks very nice - the early wooden cases seemed to have survived much better than the later leatherette covered versions.

$25 NZ - can't go wrong!


Actually that one looks pretty good I think and would clean up well. Notice the opaque tuning knob, that is exactly the way mine looked before I repaired it.


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 Post subject: Re: NZ MADE "PACEMAKER" 1957 Transistor Radio
PostPosted: Jan Sun 26, 2020 7:35 pm 
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Location: Palos Verdes, CA
majoco - Thank you for posting the Pacemaker transistor radio that is for sale in NZ. Do you think the seller would ship the radio to the United States? I've seen transistor radios for sale in Australia on eBay and know the shipping costs are quite expensive. - Mark


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 Post subject: Re: NZ MADE "PACEMAKER" 1957 Transistor Radio
PostPosted: Jan Sun 26, 2020 7:51 pm 
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Quote:
Do you think the seller would ship the radio to the United States


I'll ask him....

Watch this space.....

...and the answer is here under "Questions and Answers"....

https://www.trademe.co.nz/Browse/Listin ... 2505956015

...but first you have to win the auction. I can bid on your behalf unless you want to join "Trademe" in case some other gem-in-the-rough pops up. To save getting 'auction fever' I usually calm down a bit then set myself a realistic maximum bid, enter that and tick the "auto-bid" box - your bid will beat every other bid by a dollar until you reach your maximum - you can of course put in another bid.

I'll do some research regarding postage fees.

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 Post subject: Re: NZ MADE "PACEMAKER" 1957 Transistor Radio
PostPosted: Jan Sun 26, 2020 11:40 pm 
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Joined: Aug Sat 16, 2014 2:19 am
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Location: Palos Verdes, CA
majoco - I've bought a few vintage transistor radios from sellers in Canada on eBay, but only bid as they showed the cost to ship the radios to the US. I did help my neighbor sell his 1958 Chevrolet pickup truck to a buyer in New Zealand, but we drove the truck to someone who specialized in exporting vehicles overseas at the Port of Long Beach and the buyer paid all the costs. Any idea of how much a Pacemaker transistor radio is worth as I've never seen one for sale? I keep a cost history of past transistor radio sales that I look at before I figure out what is my maximum eBay bid, but have no idea what a Pacemaker radio is worth. Thanks! - Mark


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 Post subject: Re: NZ MADE "PACEMAKER" 1957 Transistor Radio
PostPosted: Jan Wed 29, 2020 8:27 pm 
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I have no idea what the radio would be worth in the US, the one on TradeMe looks to be in good condition and if it goes for NZ$25 then it's a bargain here.

I did some sums on the dimensions given plus some substantial packing - then using the NZ Post web page for delivery to the US the cost comes to about NZ$50 - IMHO that probably kills it. Then of course you know nothing about the vendor - he might just drop it into a cardboard box........ :(

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 Post subject: Re: NZ MADE "PACEMAKER" 1957 Transistor Radio
PostPosted: Jan Wed 29, 2020 9:17 pm 
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Location: Palos Verdes, CA
majoco - Thank you for contacting the seller of the Pacemaker transistor radio and for posting an estimate of shipping the radio to the US. I can understand that the seller would rather not sell the radio to someone overseas as I've had to fill out export papers for items shipped to other countries at work. - Mark


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 Post subject: Re: NZ MADE "PACEMAKER" 1957 Transistor Radio
PostPosted: Jan Wed 29, 2020 11:26 pm 
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majoco wrote:
I can bid on your behalf unless you want to join "Trademe" in case some other gem-in-the-rough pops up.

He can't.
Quote:
Membership is limited to residents of New Zealand and Australia.

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