Cleaning Circuit Boards & Chassis

[AUdubon5425]

Well, I'm taking my first dive into cleaning a chassis.

I pulled the back off of this little '71 Motorola 12" portable, and it was obvious water had been leaking through the top at some point - and it was a smoker's set to boot. I couldn't visibly see what shape many of the resistors were in.

So I pulled the chassis, leaned it against the fence, and soaked it with Simple Green.

A toothbrush helped, but light water pressure sufficed as the Simple Green did most of the work. Now it's in the sun drying out.

Many of the tube shields have rust on them. Should I be concerned with this? They were soldered to the board so I haven't disturbed them yet.

Also, I found no markings where this was made. Was Motorola still manufacturing these small sets in America in 1971?

[AUdubon5425]

The board looks much better now, but you can see the surface rust on all the metal parts on the chassis:


The corner of the cabinet is pretty much what the whole topside of the chassis looked like before:

[Reece]

That's what you have to do sometimes to clean a gunky chassis. Some put circuit boards in the dishwasher! But you do have to be careful of coils. You want to put this in a warm, dry (ha! find dry in Louisiana! I know; I grew up in Beaumont, TX!) place for several days. I like to shine a light bulb on a chassis or put it in the sun to dry it out for a couple of days before trying to power up.

[holmesuser01]

Originally Posted by Reece

That's what you have to do sometimes to clean a gunky chassis. Some put circuit boards in the dishwasher! But you do have to be careful of coils. You want to put this in a warm, dry (ha! find dry in Louisiana! I know; I grew up in Beaumont, TX!) place for several days. I like to shine a light bulb on a chassis or put it in the sun to dry it out for a couple of days before trying to power up.

Ive washed chassis, too, but I dry them on low in the oven for an hour. Never had a set die from this.

[dieseljeep]

I sold a lot of that model when I was selling Motorola products. I think that was one of the last USA built sets. Very reliable, and a lot better performer than the simular GE sets. IIRC it had a transistor 2nd IF. The later ones were made in Tiawan.

[AUdubon5425]

I hope she's salvageable - I'm letting the chassis dry out this week inside the shed. Of course, it'll be raining for the next few days so I'll give it until the weekend to be safe.

The 2nd IF is transistor - I think there's about 4 in there total.

[dieseljeep]

That Motorola is a 12" set. I bought one on ebay several years ago. It still has the standard neck on the CRT instead of that peanut neck. IIRC the CRT is a Sylvania sourced tube.

[holmesuser01]

Originally Posted by dieseljeep

I sold a lot of that model when I was selling Motorola products. I think that was one of the last USA built sets. Very reliable, and a lot better performer than the simular GE sets. IIRC it had a transistor 2nd IF. The later ones were made in Tiawan.

I got a GE 12" for Christmas in 1971, I think. It worked until the plastic handle broke about 4 years later. I liked the Motorolas, too.

[AUdubon5425]

Oops - you're right, it is a 12". The CRT is a 12BUP4C EIA 169

[Findm-Keepm]

Originally Posted by AUdubon5425

Oops - you're right, it is a 12". The CRT is a 12BUP4C EIA 169

RETMA/EIA 169=Motorola. Sylvania would be 312, GE 188, RCA 274, and Zenith/Rauland 343.