Friden 130 - UK Vintage Radio Repair and Restoration Discussion Forum

gingpeakin · 22nd Sep 2011, 9:02 pm

I've decided to clean up my Friden 130 calculator after 30 odd years.
It was given to me when I was at school by a friend of my dad - they were throwing it away from the office where he worked.
This was the first transistorised calculator - http://www.oldcalculatormuseum.com/friden130.html
The first electronic calculator was the Anita Mk8 which used thyratrons, of which I also have an example which I hope to bring back to life sometime.
The Friden worked for a bit then the mains transformer gave up the ghost which I gather was quite common. At the time I replaced it with a nice Marinair transformer that I had lying around. It produces 24-0-24, 90, 50 and 50V in a strange combination of windings. I can't remember exactly what I did but the 24-0-24 winding feeds the +6V supply, the 24V feeds the -12V supply and the 90V feeds the-80V supply. These are all shunt regulated by a combination of 2N669s and a big zener diode. The single 50V winding I fed to a second 24-0-24 to 6.3V transformer for the CRT heater.
This worked for ages, although I'm not sure why.
After many years and a house move I switched it on and nothing, not even any smoke. I really was very untidy all these years ago so I thought I'd do a proper repair. At the moment I'm trying to work out the consumption of the various supply rails to see if I can rationalise the transformer arrangements.
I'll post some pictures and the power supply circuit later...

Ging

gordonrussell · 23rd Sep 2011, 3:59 am

Hello Ging. I to have a Friden calculator - EC 132 + later models. My father worked for Friden in 1960s early 70s. I have restored the EC132 to full working order. Replaced the EHT voltage multiplier section along with cleanup and power transistor. Thrilled to get it working. I have the wiring diagram if useful.
Best wishes

Gordon

TriMan66 · 23rd Sep 2011, 10:01 am

Hi Ging,
That was fascinating to read about the Friden 130.
It will great to the photos and follow the repair.

Craig

gingpeakin · 24th Sep 2011, 12:09 pm

Hi Gordon

I'm sure there will be others interested to see the circuit of you 132 - there must be loads of similarities.

If you can't post it here then I've sent you a pm.

Ging

gordonrussell · 25th Sep 2011, 12:50 pm

Hello Ging

I am unclear how to attach the power supply circuit for EC 132 and send to you or what pm is?

Please advise.

Gordon

Darren-UK · 25th Sep 2011, 2:21 pm

PM = Private Message. As Ging's sent you one, you should have notification of it at top right, below where it says "Welcome gordonrussell".

To attach the circuit, image or whatever, click Post Reply (not Quick Reply) then scroll down to and click on Manage Attachments.

gordonrussell · 26th Sep 2011, 1:23 am

Hello Ging

I have posted photos on my profile - public. The EHT circuit can be found there.

Regards, Gordon

gingpeakin · 29th Sep 2011, 10:56 am

Here's the circuit - the EHT section is a bit cruder than the 132's.

I don't know what the original transformer spec was - the diagram shows the voltages of my replacement. The caurrents are as measured with all the cards and the memory unplugged. As the -80 and +6 regulators are shunts I wouldn't expect those values to change.
This all works so the fault(s) must be elsewhere...

Sadly the first thing I did when I was given this machine was to take out the CRT and build the 'New Transistorised Oscilloscope' as described in Radio and Electronics Constructor magazine of September 1975...

Ging

VintageHarry · 21st Dec 2012, 1:55 pm

Hello Gordon,

I hope that you may be getting updates from this site.

I am very interested in Friden EC130 tech data, you said you had circuits! Would you please let me know what you have - reply here or PM.

Thanks,

Harry

22nd Sep 2011, 9:02 pm	#1
gingpeakin Hexode Join Date: Mar 2009 Location: Worthing, Sussex, UK. Posts: 276	Friden 130 I've decided to clean up my Friden 130 calculator after 30 odd years. It was given to me when I was at school by a friend of my dad - they were throwing it away from the office where he worked. This was the first transistorised calculator - http://www.oldcalculatormuseum.com/friden130.html The first electronic calculator was the Anita Mk8 which used thyratrons, of which I also have an example which I hope to bring back to life sometime. The Friden worked for a bit then the mains transformer gave up the ghost which I gather was quite common. At the time I replaced it with a nice Marinair transformer that I had lying around. It produces 24-0-24, 90, 50 and 50V in a strange combination of windings. I can't remember exactly what I did but the 24-0-24 winding feeds the +6V supply, the 24V feeds the -12V supply and the 90V feeds the-80V supply. These are all shunt regulated by a combination of 2N669s and a big zener diode. The single 50V winding I fed to a second 24-0-24 to 6.3V transformer for the CRT heater. This worked for ages, although I'm not sure why. After many years and a house move I switched it on and nothing, not even any smoke. I really was very untidy all these years ago so I thought I'd do a proper repair. At the moment I'm trying to work out the consumption of the various supply rails to see if I can rationalise the transformer arrangements. I'll post some pictures and the power supply circuit later... Ging

23rd Sep 2011, 3:59 am	#2
gordonrussell Retired Dormant Member Join Date: Sep 2011 Location: Adelaide, Australia. Posts: 3	Re: Friden 130 Hello Ging. I to have a Friden calculator - EC 132 + later models. My father worked for Friden in 1960s early 70s. I have restored the EC132 to full working order. Replaced the EHT voltage multiplier section along with cleanup and power transistor. Thrilled to get it working. I have the wiring diagram if useful. Best wishes Gordon

23rd Sep 2011, 10:01 am	#3
TriMan66 Pentode Join Date: Jun 2009 Location: Royston Posts: 120	Re: Friden 130 Hi Ging, That was fascinating to read about the Friden 130. It will great to the photos and follow the repair. Craig

24th Sep 2011, 12:09 pm	#4
gingpeakin Hexode Join Date: Mar 2009 Location: Worthing, Sussex, UK. Posts: 276	Re: Friden 130 Hi Gordon I'm sure there will be others interested to see the circuit of you 132 - there must be loads of similarities. If you can't post it here then I've sent you a pm. Ging

25th Sep 2011, 12:50 pm	#5
gordonrussell Retired Dormant Member Join Date: Sep 2011 Location: Adelaide, Australia. Posts: 3	Re: Friden 130 Hello Ging I am unclear how to attach the power supply circuit for EC 132 and send to you or what pm is? Please advise. Gordon

25th Sep 2011, 2:21 pm	#6
Darren-UK Retired Dormant Member Join Date: Apr 2003 Location: Blackpool, Lancashire, UK. Posts: 4,061	Re: Friden 130 PM = Private Message. As Ging's sent you one, you should have notification of it at top right, below where it says "Welcome gordonrussell". To attach the circuit, image or whatever, click Post Reply (not Quick Reply) then scroll down to and click on Manage Attachments.

26th Sep 2011, 1:23 am	#7
gordonrussell Retired Dormant Member Join Date: Sep 2011 Location: Adelaide, Australia. Posts: 3	Re: Friden 130 Hello Ging I have posted photos on my profile - public. The EHT circuit can be found there. Regards, Gordon

21st Dec 2012, 1:55 pm	#9
VintageHarry Retired Dormant Member Join Date: Dec 2012 Location: Melbourne, Australia. Posts: 2	Re: Friden 130 Hello Gordon, I hope that you may be getting updates from this site. I am very interested in Friden EC130 tech data, you said you had circuits! Would you please let me know what you have - reply here or PM. Thanks, Harry