Cleaning old circuit boards and components without destroying them - what to use?

[Dekatron42]

I just acquired a Xerox 3600 Photocopier counter, the semiconductor version of the older Trochotron based 2400 unit - it has similiar/identical function when counting copies made.

Now, this unit looks like it has been sitting in a car shop or an old attic/barn for many years. I did clean out a lot of spiderwebs, egg sacks from spiders and a few flowers and sticks.

Some of the TO18- & TO99-cased semiconductors have started to get small green blobs on them, probably from copper corroding, and some have started to rust due to their iron casing (2N3054s). There is also a lot of dust and what looks like some thin oil over a lot of the components and circuit boards.

I'll check all of the components for function and replace as few as possible to keep it as original as I can. Some of the Mullard Tropical Fish capacitors have broken and the legs have come off, one transistor has had one of its legs cut off for some reason. Last week I got a bag of these Mullard capacitors when I bought older components for another restoration project so now they too will come to use.

Now, I've never had to do more than some dusting on other old equipments that I've bought so now I need help from "experts" on what cleaning liquids to use to spare the components and circuit boards.

Photos doesn't work in Neonixie-L for me and some other memebers so unfortunately I can't include any just yet (time to move from Google Groups as it is working so poorly since their new design?).

/Martin

[Adrian Pardini]

On Fri, 15 Jan 2021 at 20:56, Dekatron42 <martin....@gmail.com> wrote:
>
> Photos doesn't work in Neonixie-L for me and some other memebers so unfortunately I can't include any just yet (time to move from Google Groups as it is working so poorly since their new design?).

Photos arrived fine here, I really like the look of those numbered disks.


--
Adrián Pardini

[Charles MacDonald]

for some reason, the photos arrived at the very bottom of the e-mail.
Not the first time I have received a message that way.


--
Charles MacDonald VA3CPY Stittsville Ontario
cm...@zeusprune.ca Just Beyond the Fringe
No Microsoft Products were used in sending this e-mail.

[Nicholas Stock]

@Dekatron42 Which browser are you using? Alas (in my recent experience) a lot of Google's services aren't playing well with Safari or Firefox but appear to work (obviously) well with Chrome. Your photo issue may be browser specific? I can't see any other settings in the group that would change photo behaviour....

Cheers,

Nick (Mod)

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[Kevin A.]

I would use distilled water to begin with. I always solder with water soluble flux so the distilled water makes your boards squeaky clean after soldering too.

If you need more cleaning power I would use regular isopropyl alcohol. 

I only use kimwipes for all of my rework as they are absorbent and very low lint. 

On Fri, Jan 15, 2021, 6:49 PM Dekatron42 <martin....@gmail.com> wrote:

I just acquired a Xerox 3600 Photocopier counter, the semiconductor version of the older Trochotron based 2400 unit - it has similiar/identical function when counting copies made.

Now, this unit looks like it has been sitting in a car shop or an old attic/barn for many years. I did clean out a lot of spiderwebs, egg sacks from spiders and a few flowers and sticks.

Some of the TO18- & TO99-cased semiconductors have started to get small green blobs on them, probably from copper corroding, and some have started to rust due to their iron casing (2N3054s). There is also a lot of dust and what looks like some thin oil over a lot of the components and circuit boards.

I'll check all of the components for function and replace as few as possible to keep it as original as I can. Some of the Mullard Tropical Fish capacitors have broken and the legs have come off, one transistor has had one of its legs cut off for some reason. Last week I got a bag of these Mullard capacitors when I bought older components for another restoration project so now they too will come to use.

Now, I've never had to do more than some dusting on other old equipments that I've bought so now I need help from "experts" on what cleaning liquids to use to spare the components and circuit boards.

/Martin

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[Toby Thain]

On 2021-01-15 7:07 p.m., Charles MacDonald wrote:
> On 2021-01-15 6:58 p.m., Adrian Pardini wrote:
>> On Fri, 15 Jan 2021 at 20:56, Dekatron42 <martin....@gmail.com>
>> wrote:
>>>
>>> Photos doesn't work in Neonixie-L for me and some other memebers so
>>> unfortunately I can't include any just yet (time to move from Google
>>> Groups as it is working so poorly since their new design?).
>>
>> Photos arrived fine here, I really like the look of those numbered disks.
>>
>>
>
> for some reason, the photos arrived at the very bottom of the e-mail.
> Not the first time I have received a message that way.
>
>

"Contents may have settled in transit." :-)

--Toby

[Yohan Park]

I usually start with lukewarm water and dish wash.
I don't see the need for distilled water here. Why? Regular water won't harm any plastics, bakelite or circuits...
If soapy, lukewarm water still leaves unwanted coloring (tar from cigarettes is very common) I use IPA.
If that fails too I, very carefully, try using something like naphtha. Acetone is a last resort but beware: using it on any kind of plastic may result in unrecoverable damage.

[Dekatron42]

@Pramanicin: I tried Firefox (my first choice), Chrome and lastly Edge as a last resort - the only thing I got to see was the name of the phot included in all three browsers, I closed the browsers and restarted them but nothing showed.

Nice that some of you saw the photos, I'll add some more so that you can see the sorry state of the circuit boards.

/Martin

[Dekatron42]

Here are some more photos, hope you can see them!

/Martin

[Dekatron42]

[Dekatron42]