M. W. I. M. M. WANTED & Projects page.
A main problem with the Racal series of sets is that some need a 24v supply. Most have batteries and though its easy to get replacement
D cells to renew old batteries the Racal chargers are not so common. One simple solution is used here. Take a standard wall mounted battery
eliminator, find a 12v one rated at about 1 Amp, and with slight modification it can be used to charge the 24v units. The original circuit
is given below.
The moddified circuit is now given. Break open the moulded plastic case by cutting with a Stanly knife and remove the existing diodes
and caps etc. A voltage doubler circuit is used and once the unit is resealed, with super glue, it makes a nice compact charger.
The original lead probably had a miniature plug on the end. I replaced this with a pair of croc clips so that I can quickly clip
the charger onto any of the various 24v batteries here. The diodes are 1N4007 and the caps can be anything, but equal, say 2200uf at 35V.
Of course the charger is not regulated. I would suggest you give all the batteries a good charge off a regulated supply, if
they are 1700mA D cells then charge at 170mA for 16 hour, then use the simple charger when on holiday say just to top up the
batteries as you use them. You could of course squeeze in a regulator circuit into the wall charger if you want.
Projects presently on the go here:
Restoration of a G and H2S station.
So far, I have the G and H2S indicators, some psu's and
the rotating head of the scanner unit. If anyone has any info on the Type 51
I would welcome a copy. Also, circuits for the 182 H2S and the Type 62 and 95
Indicators for G.
********* Pictures by G4BXD are G4BXD copyright ********