This beautiful, small, new piece of technology from the eighties has been added to my collection. It is a small tube radio receiver with radio part called CIRT-2097T from the manufacturer Broksonic (according to Internet research it is an US company). The device I received with the attribute “defective” quite cheap on a flea market platform. So I thought, the risk can be taken and risk a repair attempt. What great things can not be broken – if it’s not just the picture tube.
After a short functional test with the plug-in power supply, it soon became clear that nothing was working. No picture – no sound, no nothing. Since the device also has a battery compartment, I next wanted to try to feed the power via the battery terminals to see if there may already be a problem. And there it was already – the problem. The battery cover was almost impossible to get off, it held as glued. After some back and forth, I got the lid but then non-destructive and it revealed the cause of “jamming” or better “gluing”. There were still batteries in the battery compartment (probably for 20 or more years). They were in a bad condition, totally corroded and leaked. In part, the outer coat of the cell was corroded and no longer available. Oh dear – I thought, hopefully the leaked dielectric did not move inside the unit and did damage there. There was nothing left for me to do but to disassemble and check everything. And then the evil manifested itself:
About a quarter of the TV board had come in contact with the battery fluid. And the stuff has done a great job, etched away almost all the traces and leads from components.
So I first tried with PCB cleaner to remove all the crystals and the rest of the battery juice to get a closer look at the damage. A few random measurements with the ohmmeter quickly showed that many traces were severed. So it did not help, the tracks had to be uncovered. Only then would a reasonable repair possible.
With a rotating brass wire brush, I then began to remove the etched areas, remove the remains of the solder resist and expose the copper traces.
After the rough preliminary work had the glass brush ran. Only with that it was possible to remove all paint and corrosion residues and finally expose the traces. A tedious job …
… but finally it was possible to uncover and repair all damaged areas. Some resistors and capacitors also had to be renewed because their leads were also in poor condition.
After the repair, a bump test could then be carried out – lo and behold, there was no further error and the device was working properly again. So I was able to protect the repaired area of the board with solder varnish from renewed corrosion and reassemble the device.
Finally, here is an overview of the technical data:
vendor: Broksonic (US-Firma New York)
year of production: ca. 1982
model: TV+FM Empfänger portable
screensize: 2 Zoll SW Bildröhre
bands: AM, FM, SW (Radio), VHFI,VHFIII,UHF (TV)
VHF Kanal 2-13(US), 2-12 (E)
UHF Kanal 14-83(US),21-69(E)
supply: battery or accu, AC with adaper
supplyvoltage: accu 6V, battery 6×1.5V AA
speaker: dynamic 16 Ohms speaker
dimensions: 150x53x202 mm (BxHxT)
weight: ca 1.1kg