BT oscillator no. 87F - batteries - UK Vintage Radio Repair and Restoration Discussion Forum

oldmoley1 · 25th Nov 2015, 6:18 pm

I have an oscillator 87F of which the batteries have expired completely. The label on the front of the unit states that the replacement is "dry cell No. 30". I haven't so far been able to locate this battery, or a suitable alternative. Does anyone know what battery is likely to have replaced this item, and if so, where I might be able to get a couple from please?

Dimensions are 2 1/4" high, 1 1/4" across. No idea of the voltage I'm afraid. I have attached some photos which I hope will help.

Many thanks

g8jzyian · 25th Nov 2015, 7:41 pm

Hi
This site http://www.telephonesuk.co.uk/images...llator_87F.jpg
Gives the battery as a 6F90 which is a pp7.
PP7s are available at a price from CPC.
If it were mine I would look at restuffing the cases.

Regards

Ian

Dave Moll · 25th Nov 2015, 7:53 pm

Height is about right for a PP7 at 63mm, but at 46mm (1¾"), the PP7's depth and width are a bit greater. Is there room in the compartment for that extra half inch?

It would appear that CPC sell them at just under a tenner a time. They may be available cheaper elsewhere.

edit: Ian posted while I was composing and Googling.

Herald1360 · 25th Nov 2015, 10:05 pm

Since it's now known to be 9V, a 6AA or if that's too big 6AAA holder using the connector on the top of the old battery as an adaptor would work just fine and ease supply issues.

Dave Moll · 25th Nov 2015, 11:13 pm

I think the PP7 has the larger connectors like a PP9, and finding a holder with connectors of that size may be a problem. Of the holders I've come across with integral connectors, all have been PP3-sized.

Herald1360 · 26th Nov 2015, 1:35 pm

I was thinking of wire ended battery holders and soldering the top of the old battery to the flying leads. Alternatively replace the PP7 connector on the instrument with a PP3 type or make up a PP3-PP7 adaptor lead.

Watch out for polarity. The male stud on the battery is positive and the clip is negative. Vice versa on the instrument.

FIXITNOW · 26th Nov 2015, 1:57 pm

it looks to be a plastic case if so a quick wack should snap the seal round the top pull the old inners out and solder in a pp3 clip and just fit a pp3 inside
that's what I do to old pp7's on a pp9 I use a 6 AA holder

Herald1360 · 26th Nov 2015, 5:48 pm

Looks like a 6AAA holder will fit inside a PP7 case. A PP3 is only 6AAAA cells in alkaline format.

Oldcodger · 6th Dec 2015, 5:24 pm

I may be being a tad pedantic (if so I apologise), but on the set (osc+amp) I have, the oscillator had two connectors (so presumably two batteries), each as said being PP7. I had mine running (and working for it's living) with two sets of six AA cells in a convert pack . I would think that the size I used would fit inside a PP7 CASE.

25th Nov 2015, 6:18 pm	#1
oldmoley1 Tetrode Join Date: Apr 2014 Location: Northampton, Northants, UK. Posts: 84	BT oscillator no. 87F - batteries I have an oscillator 87F of which the batteries have expired completely. The label on the front of the unit states that the replacement is "dry cell No. 30". I haven't so far been able to locate this battery, or a suitable alternative. Does anyone know what battery is likely to have replaced this item, and if so, where I might be able to get a couple from please? Dimensions are 2 1/4" high, 1 1/4" across. No idea of the voltage I'm afraid. I have attached some photos which I hope will help. Many thanks Attached Thumbnails

25th Nov 2015, 7:41 pm	#2
g8jzyian Pentode Join Date: Jan 2009 Location: Liverpool, Merseyside, UK. Posts: 149	Re: Bt oscillator no. 87f - batteries Hi This site http://www.telephonesuk.co.uk/images...llator_87F.jpg Gives the battery as a 6F90 which is a pp7. PP7s are available at a price from CPC. If it were mine I would look at restuffing the cases. Regards Ian

25th Nov 2015, 7:53 pm	#3
Dave Moll Dekatron Join Date: Feb 2005 Location: West Cumbria (CA13), UK Posts: 6,130	Re: Bt oscillator no. 87f - batteries Height is about right for a PP7 at 63mm, but at 46mm (1¾"), the PP7's depth and width are a bit greater. Is there room in the compartment for that extra half inch? It would appear that CPC sell them at just under a tenner a time. They may be available cheaper elsewhere. edit: Ian posted while I was composing and Googling. __________________ Mending is better than Ending (cf Brave New World by Aldous Huxley)

25th Nov 2015, 10:05 pm	#4
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,536	Re: Bt oscillator no. 87f - batteries Since it's now known to be 9V, a 6AA or if that's too big 6AAA holder using the connector on the top of the old battery as an adaptor would work just fine and ease supply issues. __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

25th Nov 2015, 11:13 pm	#5
Dave Moll Dekatron Join Date: Feb 2005 Location: West Cumbria (CA13), UK Posts: 6,130	Re: Bt oscillator no. 87f - batteries I think the PP7 has the larger connectors like a PP9, and finding a holder with connectors of that size may be a problem. Of the holders I've come across with integral connectors, all have been PP3-sized. __________________ Mending is better than Ending (cf Brave New World by Aldous Huxley)

26th Nov 2015, 1:35 pm	#6
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,536	Re: BT oscillator no. 87F - batteries I was thinking of wire ended battery holders and soldering the top of the old battery to the flying leads. Alternatively replace the PP7 connector on the instrument with a PP3 type or make up a PP3-PP7 adaptor lead. Watch out for polarity. The male stud on the battery is positive and the clip is negative. Vice versa on the instrument. __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

26th Nov 2015, 1:57 pm	#7
FIXITNOW Octode Join Date: Feb 2007 Location: Ely, Cambridgeshire, UK. Posts: 1,976	Re: BT oscillator no. 87F - batteries it looks to be a plastic case if so a quick wack should snap the seal round the top pull the old inners out and solder in a pp3 clip and just fit a pp3 inside that's what I do to old pp7's on a pp9 I use a 6 AA holder

26th Nov 2015, 5:48 pm	#8
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,536	Re: BT oscillator no. 87F - batteries Looks like a 6AAA holder will fit inside a PP7 case. A PP3 is only 6AAAA cells in alkaline format. __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

6th Dec 2015, 5:24 pm	#9
Oldcodger Nonode Join Date: Oct 2014 Location: West Midlands, UK. Posts: 2,181	Re: BT oscillator no. 87F - batteries I may be being a tad pedantic (if so I apologise), but on the set (osc+amp) I have, the oscillator had two connectors (so presumably two batteries), each as said being PP7. I had mine running (and working for it's living) with two sets of six AA cells in a convert pack . I would think that the size I used would fit inside a PP7 CASE.