Ultra TR100 battery wires

[poppydog]

My daughter bought me a couple of early Fathers Day presents, both were radios one of them is an Ultra TR100 which needs a bit of work. It originally was powered by a couple of AD28 batteries, however somebody has wired it rather crudely to work off one PP9. My question is: Is it ok to run the radio like this, without any other modification? The radio shows a little life, quietly crackling out of the speaker but that's it. It draws 40ma when first switched on then not long after starts to draw copious amounts of current very quickly. The original battery wiring doesn't look like it has been messed with other than the connectors for the AD28's cut off. I have posted some pictures of the wiring and as I said all I want to know is is it ok to keep it wired for the PP9, obviously after it is tidied up a little.

Regards
Poppydog

p.s. note the very hairy/whiskery transformer.

[Records]

I wouldnt think running it off a PP9 would harm it as 2 AD28's makes 9V. The original batteries are still available at £4.60 each. I would get the radio working then experiment with both types of battery, see how long they last.

[Cobaltblue]

The original design was 4.5 + 4.5 with the centre tap going to the speaker.

You can run it off single 9V but you need to add a capacitor in series with the speaker 470uF should be more than enough the cacacitor returning to the -ve or +ve supply to suit you preference.

Cheers

Mike T

[Records]

I stand corrected, so do you think if that radio has been run off a single 9v for any amount of time without the capacitor it may have damaged it ?

[Cobaltblue]

If the speaker was crackling it was connected to something !

Cheers

Mike T

[60 oldjohn]

That extra brown wire on the battery connector, is it connected to an extra cap as Mike says?


John.

[Cobaltblue]

Here is the output stage as originaly designed

Cheers

Mike T

[poppydog]

Thanks for all the replies

Originally Posted by Records

I stand corrected, so do you think if that radio has been run off a single 9v for any amount of time without the capacitor it may have damaged it ?

I was wondering the same as TR6 (XC101) is getting very hot.

Originally Posted by Cobaltblue

If the speaker was crackling it was connected to something !

I am not quite sure what to make of that reply.

Originally Posted by 60 oldjohn

That extra brown wire on the battery connector, is it connected to an extra cap as Mike says?

No, the brown wire is not connected to an extra cap, its untouched.

Thanks for the snippet Mike, I'll attempt to send a revised one in a bit.

Regards
Poppydog

[Cobaltblue]

Originally Posted by poppydog

I am not quite sure what to make of that reply.

If the 9V battery was only connected to the outer connections

such as top Battery -ve and bottom battery +ve (total 9V) then the speaker which is connected to the centre tap would be connected to nothing hence it would not crackle.

For the speaker to crackle the common connection must be connected to something to complete the circuit.

You should not need to rely on snips get the full circuit.

If you are restoring any number of sets I highly recomend Pauls Service disc it may seem a big outlay but considering the convenience and the amount of work it entailed its excellent value for money.

Cheers

Mike T

[poppydog]

The sheet I have got came from up top right. I am going to post a revised snippet with modification for the 9v battery. I would like members just to cast their eye over it to see if its right.

Regards
Poppydog

[AC/HL]

Yes, that's how it was done when PP11s also became obsolete.

[poppydog]

Thanks for the confirmation that its ok. Now I can carry on. Regards Poppydog

[poppydog]

Going through my junk I came across some NOS Wima 500uF 10v caps, could I use these? Is the capacitance too high and the voltage to low?, or should I just use new?

Regards Poppydog.

[Herald1360]

They should be OK. Try one and see.......

[poppydog]

I thought I would post these pics on here for the next poor chap whose original TR100 battery leads have been chopped and discarded . I probably could have used a much smaller (physical size) modern capacitor but I had just as well use this nos one although it was rather large and the leads were quite thick . This radio has had a whole heap of issues but the main problem I have now is after replacing a couple of the black Hunts I now have Talk Sport, that's supposed to be on MW, at one end of LW so I might start a new thread hoping to sort this issue .

Regards
Poppydog

[Restoration73]

Ideally, components should mount on the non solder side though.
http://www.maplin.co.uk/p/electrolyt...ucky-bag-n26bg

['LIVEWIRE?']

Whereabouts on LW are you receiving TalkSport? Here in Oxfordshire Absolute Radio (1197 & 1215kHz can, on some radios, be heard on about 270kHz, which I put down to poor I.F. rejection in the receiver (275kHz + 940kHz# 1215kHz, 940 being of course 2 x 470) A similar thing could be happening with TalkSport's 1089kHz frequency being reproduced at around 169-179kHz, dependant on the I.F. When BBC R. Oxford used to be on 1485kHz, one radio I had at the time would receive it on545kHz for the same reason

[poppydog]

Originally Posted by Restoration73

Ideally, components should mount on the non solder side though.
http://www.maplin.co.uk/p/electrolyt...ucky-bag-n26bg

I thought I would put these pics and stuff on here so it may help someone in the same predicament as me. As this is a public forum I thought perhaps anyone on the outside could look on here with this same problem and not have to interact/join to get the help they need as its a fairly simple solution. I felt there was no room on the top of the board so this is the way I did it unless someone can show me otherwise. The capacitor is insulated where it needed to be, the solder joints are strong but perhaps could be a little neater (I have seen some hideous soldering on here). Maybe some help with fault finding would be more beneficial to me rather than 'finding fault' (I don't mind being told when I have done something wrong), also perhaps you can explain what the capacitor lucky bag link is for? Such a shame

[AC/HL]

The operative word is ideally, it will work just fine as long as it is electrically and mechanically sound. Traditionally, components on the printed side indicate mods, which of course this is, so nothing to worry about.

[Station X]

We need more information.

Does the set work on LW?

What MW frequency does Talk Sport use in your area?

At what dial position on LW is Talk Sport received? Is it the same position at which Talk Sport is received on MW?