DIY Signal Chaser (Signal Injector)

[@benoySimon]

Thank you, indeed a fantastic simple construction, a great motivaton to build one for myself. Thank you Iain for kindly posting this.

[@charlesbrown980]

I just built the signal chaser and tested it out today. There's two things I really like about the the video and the equipment. First, it reminds me of Heathkit manuals where the electronic theory is explained and second the chaser can be used on tube or solid state equipment which makes it a really handy piece of test equipment.👍

[@iainportalupi]

I’m glad you like signal chaser. I hope it comes in handy repairing things.

[@jimnewman5596]

Hi Iain, Just built this and put it in a box and it works great, thank you putting this info out for there for other people to use for troubleshooting circuits.

[@jimnewman5596]

Great video Iain, I just learned about the signal chaser from Gregg's Vintage Workshop and watched your video and plan to build one for myself.

[@t1d100]

Thank you for your effort and graciousness in sharing this information. I know you did a lot of work for our benefit. We recognize that and appreciate it. Great project. Very well explained.

[@Apollo-p1l]

Cool. Oscillation well explained, its quite an effort to explain that circuit that completely.. Never knew about resistance wire either, no wonder it was phased out.

[@iainportalupi]

FEMADEATHCAMPCONTROL thanks. The kicker was I knew I only had enough camera battery for one take for the explanation of the oscillator.

[@greggsvintageworkshop8974]

Fantastic video, thank you! I'm definitely going to build this chaser. This will be a great addition to my shop.

[@iainportalupi]

Gregg's Vintage Workshop thanks for watching! I think you’re going to be very happy with this chaser.

[@hillbillylocksport5547]

This is exactly what I was looking for thank you

[@lengle73]

Very cool video, thanks for another great tutorial!

[@johanntiu4162]

Is there a semiconductor version of that circuit? Thank you.

[@iainportalupi]

@@johanntiu4162 I’d have to think about it a while but it wouldn’t be as simple as this vacuum circuit.

[@johanntiu4162]

@@iainportalupi Thanks. 😊

[@greggsvintageworkshop8974]

Ian where did you connect your scope on this chaser (the actual connection points) when you had it connected up? I built it and so far I'm having issues getting it to oscillate.

[@iainportalupi]

I connected the scope probe to the tip of the signal chaser and the scope’s ground to the chassis. But the signal chaser must be plugged into an isolation transformer when the scope is connected. I have found that it is picky about the tube used and the first two tubes I tried with mine wouldn’t oscillate. Both halves of the dual triode need to be well matched.

[@greggsvintageworkshop8974]

Thanks Iain, I found the issue was in the lead I used. I could read it on the scope at the end of the cap. So all is well. Thank you!

[@iainportalupi]

@@greggsvintageworkshop8974 glad you got it sorted out!

[@genestanley553]

very informative video..... a little long but good detail.... really wish it was transistorized.

[@iainportalupi]

Why do you want it transistorized?

[@cliffjones7868]

Good project, however a relay that turns on and off will make a great noise maker. Same thing as a car vibrator, on all the time, rich harmonics, simpler and no tubes to burn out. Navy used that as buzzers for finding ships wiring. When you have several wire paths, using it with some earphones you can Identify traces. A transistor oscillator will do the same thing. Like I said a fun project but there are easier designs to use.

[@t1d100]

Cliff, I fully recognize the elegance of Iain's project, but I have no experience with tube circuits. So, if you could provide a link to a newer circuit that achieves the broad spectrum oscillation and has the safe injection feature of Iain's circuit, that would be of interest to me. I look forward to seeing it. No disrespect to you, Iain. I just need to work within my knowledge base.

[@t1d100]

Seems these may be called signal injectors?

[@kevintewell6004]

How much amperage does the 12 volt transformer have to be? Also you have two pin 3 numbers on the schematic

[@iainportalupi]

Kevin Tewell any transformer 0.2A or more will do it. I fixed the schematic @18:35.

[@radiotvrepair1059]

Thanks for this vedio you can give me the number and the name of the magazine of this project

[@jimdawes7261]

Thanks Lain, I'm a bit of a newbie to electronics (less than 2 years), I've built a signal tracer (and restored 10 AA5 radios) but this device I like much better so I'm gonna build one but I have a few questions. #1 Does the amp rating of the 12.6v transformer matter? #2 Where did you attach your chassis ground?

[@iainportalupi]

Jim Dawes the tube’s filament draws 0.125A so any transformer 0.2A or over would be fine. The one I used was a big 3A one simply because I had it on the shelf, but it is total over kill for what it’s doing. By chassis ground do you mean the other side of the safety cap? If so I just connected it to the center lug of the terminal strip because that got screwed to the metal enclosure.

[@benoySimon]

@@iainportalupi I had the same question as Jim Dawes, so now it's clear after your kind reply. Only change for me is voltage in Austria =230V. Many thanks again.

[@benoySimon]

@@iainportalupi Ian, In eagerly attempting to build your magnificient project that I was inspired to build, I have almost collected all the components as you have brilliantly explained in your video. The only question that still remains is the following: I had ordered a dual input/output (Hammond 185C12) transformer PRI/SEC: 115x2 - 6.3x2 vac @2A. However, on checking, output reads 14.7 vac w/out load. I suppose this is too much for the filament at the outset. Would appreciate your kind advice as this is my first shot at valves. Thanks a million.

[@kevintewell6004]

Would a aluminum box work or does it have to be steel? Might be a dumb question LOL.

[@iainportalupi]

Kevin Tewell either would be fine. The one I used was aluminum.