Hameg HM 307 Oscilloscope Restoration - UK Vintage Radio Repair and Restoration Discussion Forum

Ian_M5AXA · 11th Sep 2022, 1:59 pm

This story starts back in 1983 when i was teenage studying electronics. Keen to look inside any electronic device my dad gave me a cardboard box of parts and what was clearly an oscilloscope. He found it in a skip at a local college that he was delivering to. The idea was to give me an opportunity to experiment with the scope. To be honest without a schematic or a service manual it was going nowhere. So it go put away in the attic along with other bits and pieces. It stayed in my parents attic until they moved back in 2015 when they gave me this cobweb ridden box contain this old scope in bits. By this time I had my own scope and a busy work life so I wasn't exactly keen to do anything with it.

Then Covid came along and along and with it a lots of free time too. So I dug out the old Hameg out and decided that I would attempt to restore it. Starting with a good vacuum and clean I could see that although in bits, all the necessary parts were there. The electrolytic capacitors was as I expected in need of replacement. All were common values so those all got replaced and then I powered it slowly with a variac. Initially there was an issue with frame collapse which may have been the original reason why it was found in bits. The frame collapse turned out to be a faulty deflection transistor. Once the scope was up and running I used my works recently calibrated Fluke scope as a reference with an signal generator to calibrate the HM 307 with. What was really nice is that I discovered that this scope had a built in component tester in it which worked perfectly.

Many thanks for reading.

Ian

Radio Wrangler · 11th Sep 2022, 2:10 pm

Welcome to the forum!

Plenty of other Hamegs in here. Good basic scopes.

David

Ian_M5AXA · 12th Sep 2022, 1:24 am

Thanks for your reply and warm welcome David.

Have a nice week.

PJC58-Hythe · 12th Sep 2022, 12:54 pm

Welcome Ian, what a great lockdown project. The fact all the parts have been in a loft and you have still managed to salvage a working scope out of them is pretty amazing.

Great to see it working and that it had the added bonus of a component tester, well done.

Ian_M5AXA · 13th Sep 2022, 12:37 pm

Hi Peter,
Many thanks for acknowledging my post. Yes well pleased with the outcome of this project. The easy availability of service manuals online has really helped in restoring this old scope.

Regards

Ian Bassett
M5AXA

newlite4 · 15th Sep 2022, 8:03 pm

Nice job Ian. I have the later Indian made version of this Hameg, it is branded Harris. The component test feature is so good that I leave it on that setting and use a Telequipment D32 for general work. It is small enough to keep on the bench so it is always ready.
Neil

11th Sep 2022, 1:59 pm	#1
Ian_M5AXA Diode Join Date: Sep 2022 Location: Bristol, UK. Posts: 3	Hameg HM 307 Oscilloscope Restoration This story starts back in 1983 when i was teenage studying electronics. Keen to look inside any electronic device my dad gave me a cardboard box of parts and what was clearly an oscilloscope. He found it in a skip at a local college that he was delivering to. The idea was to give me an opportunity to experiment with the scope. To be honest without a schematic or a service manual it was going nowhere. So it go put away in the attic along with other bits and pieces. It stayed in my parents attic until they moved back in 2015 when they gave me this cobweb ridden box contain this old scope in bits. By this time I had my own scope and a busy work life so I wasn't exactly keen to do anything with it. Then Covid came along and along and with it a lots of free time too. So I dug out the old Hameg out and decided that I would attempt to restore it. Starting with a good vacuum and clean I could see that although in bits, all the necessary parts were there. The electrolytic capacitors was as I expected in need of replacement. All were common values so those all got replaced and then I powered it slowly with a variac. Initially there was an issue with frame collapse which may have been the original reason why it was found in bits. The frame collapse turned out to be a faulty deflection transistor. Once the scope was up and running I used my works recently calibrated Fluke scope as a reference with an signal generator to calibrate the HM 307 with. What was really nice is that I discovered that this scope had a built in component tester in it which worked perfectly. Many thanks for reading. Ian Attached Thumbnails

11th Sep 2022, 2:10 pm	#2
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,864	Re: Hameg HM 307 Oscilloscope Restoration Welcome to the forum! Plenty of other Hamegs in here. Good basic scopes. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

12th Sep 2022, 1:24 am	#3
Ian_M5AXA Diode Join Date: Sep 2022 Location: Bristol, UK. Posts: 3	Re: Hameg HM 307 Oscilloscope Restoration Thanks for your reply and warm welcome David. Have a nice week.

12th Sep 2022, 12:54 pm	#4
PJC58-Hythe Heptode Join Date: Sep 2010 Location: Hythe, Hampshire, UK. Posts: 630	Re: Hameg HM 307 Oscilloscope Restoration Welcome Ian, what a great lockdown project. The fact all the parts have been in a loft and you have still managed to salvage a working scope out of them is pretty amazing. Great to see it working and that it had the added bonus of a component tester, well done. __________________ Peter - M0HYT - BVWS Member - GQRP Club http://www.retroworkshop.co.uk

13th Sep 2022, 12:37 pm	#5
Ian_M5AXA Diode Join Date: Sep 2022 Location: Bristol, UK. Posts: 3	Re: Hameg HM 307 Oscilloscope Restoration Hi Peter, Many thanks for acknowledging my post. Yes well pleased with the outcome of this project. The easy availability of service manuals online has really helped in restoring this old scope. Regards Ian Bassett M5AXA

15th Sep 2022, 8:03 pm	#6
newlite4 Octode Join Date: Nov 2003 Location: Bath, Somerset, UK. Posts: 1,805	Re: Hameg HM 307 Oscilloscope Restoration Nice job Ian. I have the later Indian made version of this Hameg, it is branded Harris. The component test feature is so good that I leave it on that setting and use a Telequipment D32 for general work. It is small enough to keep on the bench so it is always ready. Neil __________________ preserving the recent past, for the distant future.