One of the Most Overlooked Steps in Vintage Electronics Restorations & How to Do It So Simply...
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- Опубликовано: 5 ноя 2023
- A quick little video on a critical step that is often skipped or overlooked when restoring vintage solid-state electronics. Examples of why you should do this, and steps required to do it successfully.
Link to the product I used in this video:
amzn.to/47jFvnV 
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This guy is The MAN!
Just another important item that needs to be addressed during restoration. Thanks a lot, Mark.
I appreciate the pointers videos, I'm new to fixing vintage electronics and this is gold to people like me.
I've had old silicon heatsink compound just about turn into clay. White spirit cleans it up easily.
With TO-3 devices that just plug in, such as you demonstrated, the two leads need to be cleaned of the grease before being installed, to ensure a low-resistance connection to the socket.
A good policy is to do an electrical conductivity test with an ohmmeter, between the transistor case & the heatsink, to ensure the mica washer hasn't been damaged.
Do this test before removing the transistor as well, so you know if the circuit, by design, does or not have a deliberate connection between the heatsink & the transistor case.
Sometimes, it's easier to just use new mica washers.
Thanks Mark,
Now I understand what my Tech did to my Luxman M117 amp when a previous Tech didn’t do the restoration properly
I wouldn't use fingers to spread that thermal paste. The paste has micro particles in it that will get into your skin. Also, you introduce grease from your fingers into the thermal paste. I use a small spudger for smaller applications and an old plastic card (cleaned with IPA) for bigger applications, such as CPUs. I would also recommend using IPA and a coffee filter (no residue lint that paper towel does) to clean the surface before application.
I used to use fingers all the time in my youth (40-50 yrs ago) to apply the paste, until I discovered it was carcinogenic. I used a tool to spread the paste since. Due to the small amount used and minimal time in contact with the skin, I haven't developed any cancer or dermatitis from doing so. I don't know if the grease used these days is no longer carcinogenic or if the formulation has changed.
Coffee filter! Good idea.
Good to see you posting again!! Thanks
I just remove them, clean the mating surfaces and us the heat sink pads instead of the messy white goo. There are three things in electronic repair that find a way to make a mess. Gooey drive belts, heat sink grease, and anti-seize lube.
Pads don't transfer heat as well as properly applied thermal grease. They can't fill in all the microscopic holes.
@@audionutzjulian I don’t think the loss is that significant
The thermal transfer compound is a crucial part of servicing. Thermal silicone pads work extremely well as well. But sometimes you just want to be genuine service using original factory techniques.
The ones where they used glue on the mica are a ton of fun (pioneer sx-9000 I’m talking about you). Lots of acetone and scraping involved
you are so right about that,don't ask me how i know
excellent advice.
Totally agree, Mark! 👍
Well said! Thanks for the time.
many years ago at a telco repair shop, one of the technicians actually read what was on the tube of grease he'd been using for - like forever, "Nappy Rash Cream"..... oops.
Say “Heat Sink Grease” 3x fast. Go!
It's a twister for sure, I want to say heat shrink grease...
Two big rules in life: 1) never pass up an opportunity to pee while refueling on a long road trip, and 2) never pass up any opportunity to help our electronics manage heat and operate in a comfortable temperature zone. That said, so many of the thermal compounds just get EVERYWHERE and I'm starting to play a lot more with pads when I can get away with it in my own equipment. Well done. 73, Kenny NZ5i
I love your channel, thank you! I have gotten ahold of some 1960s vintage Nova-Tech 3 and 4 band Direction Finder portable radios. They are beautiful and they receive, but the volume is almost inaudible. Based on your videos, it would appear I need to replace the caps to get the listening volume where it should be. These guys are powered by four AA batteries. My question is, do I replace them all? Is there a meter that can test them individually? I'm a newbie in this world, but know how to de-solder and solder, lol! Thank you for your help!
it's the marketing arm of recapping that hinders this investigation ! Thanks for the video good stuff. - just as important as that heat sink compound on that CPU.
Good short video long on importance!
Heat shrink compound shrinks when it gets old.
I wonder now whether it may be worth keeping a lookout on thermal materials that don't need service. Phase Change Polymer type, or maybe Carbon film type. Phase change polymer comes as paste that cures in place or very very thin pads. In use, it melts shortly above room temperature and remains molten, and freeezes again when the device is powered down. The performance of these materials is spectacular, which is hardly needed here because well you have Mica in the path which radically limits thermal conductivity anyway and it's fine, but it doesn't volatilise and cannot separate. Perhaps it has other failure modes, who knows! Maybe it can creep out of the gap if it's uneven.
Carbon thin film seems like it would be just the thing, another forever-material, but if your hot bits aren't quite planar with the heatsink, it might have difficulty bridging that. Cheap, lower performance carbon film is available from random Chinese sellers, it's for sure used industrially at scale where you don't need spectacular performance but need reliability. Care is needed though that it doesn't extend beyond mica or whatever insulator you use, because it's going to bridge. Another massive short hazard is passing component legs through it. So i can't see it being put to good use on transistors like these.
Next thought i noticed Kafuter silicone from China like the 704 advertised as a thermally conductive material with 1.6W/mK which if true would make it better than generic white paste; it's also completely and utterly unrealistic! The material itself seems high quality, but it's not like these sellers carry any responsibility for what they claim... Elsewhere you may find 0.8 specified or nothing specified at all. If i were to bet, it's probably got 0.2-0.4W/mK similar to many Silastic types. Anyway electronics silicone like this is removable (with hindrances) but should not require service of the thermal interface itself, so semi permanent, and i bet there's actual higher performance materials of this type.
Do people have any other good thoughts?
Hi Mike, what do you think of the use of that kind of silicon and glass pads instead of the mica and the grease?
Mica is far more thermally conductive than glass.
Make sure your thermal paste is non-conductive. If you slobber some cheap stuff all over the place, you are asking for trouble.
Most important make sure you us non conductive grease they make both so make sure you pay attention to this
Naptha, AKA lighter fluid dissolves heatsink grease like magic.
How can transistors be electrically isolated from the chassie when you use metal screws to attach them to that chassie?
Generally, it's being screwed into a socket on the other side, not the chassis.
lol you say heat shrink tubing so much you cant get heat sink in your head. Is there anything wrong with using computer CPU thermal paste or is this a different product?
I know, it was tough making this one. CPU stuff is the same stuff, just marketed in a way they can charge more for it...
Make sure it is electrically non-conductive
A lot of that stuff is conductive. No go for transistors where you sink the collector. Maybe the to3p’s are ok, but not brim hats for sure.
It would have been cool to use a thermal camera before and after.
I worked on a Luxman recently to fix a recapped! Someone used Dielectric grease instead of silicone. I’m sure it will somewhat work but not as good as traditional monkey snot! And can people please buy new mica insulators! They are cheap. MG Chemical is the best
Um, Mica is always-always "dry" and that is why it has been used in very high voltage applications for over a century. Mica is reusable as long as it is laminar layers and intact. Be gentle with Mica and it will out live us all !
Power surge on your meter at the end...😣
You know it’s dry when you handle the mica without printing everything with that crap.
The computer nuts are obsessed with thermal grease as far as the CPU
There are two general reasons for that ...
CPU chips aren't cheap and they last about 30 seconds without a heat sink.
and
They fail to appreciate the life curve of these products. Most CPUs will register very low temperatures while the grease is still settling, then as the oils begin to leech out the temperature rises until the remaining compound locks in with all the gaps and brings the temperature back down where it will stay for years.
They see the temperature going up a bit and panic.
Why not just use thermal pads You like to play in th thermal grease It's called "thermal resistance "
Had some bad luck with the pads in the past...
You better off using some thin copper foil as long as it's not wider then the mica
LOL, good luck burning out your equipment. Mica is an insulator that is needed here, while copper...
If you read my comment I didn't say about removing the mica, I said make it shorter than the mica then it won't have any short, You still have an insulator, should have added to make sure the holes are big enough for the leads but I thought that might be obvious@@Omega_Mark
and resistance testing the semiconductor with a Megger insulation tester....
It's no different than the resistance to the heatseat we're not talking mega voltages here@@colonelfustercluck486
That's a transistor, not an electrolytic capacitor........ Bye, bye........!