[Yaesu] FT-107E external power supply

[k3ky@erols.com]

On 25 Mar 2002 at 8:47, Laird Tom N wrote:

> Well, after fixing the FT-101E transmitting problem, another Yaesu rig
> showed up at my bench. Funny how that happens....... My friend brought
> over a FT-107 and external power supply. The first step is getting the
> power supply to work, then the rig.
> 
> Symptoms: Supply has no output..............
> 
> After taking off the cover, I saw an obvious problem, one of the
> secondary AC leads had become unsoldered from the bridge rectifier. I
> removed all the leads and checked the diodes individually and they
> were OK. Resoldered the leads and brought the supply up on a Variac to
> see if anything was shorted. All looked OK, but only had about 8 volts
> output. Checked the four pass transistors, all OK. next the regulator
> board, the driver transistor is OK, but the TA7089M regulator IC
> appears to be bad. So now I'm at a stopping point, I can't locate an
> IC or replacement. I did find one place that had them, but they have a
> $50.00 min. order.
> 
> Anybody have one of the regulator IC's? It is an 8 pin circular linear
> regulator. Yaesu also uses them on the FT-901/902 and maybe 101ZD
> rectifier board in those rigs.
> 
> Tom Laird WC9M
> Moline, IL
> 
If I had to deal with such a problem, I would very likely design out
the odd part. After finding out the average and max current draw
on the supply, I would design a circuit with a different linear
regulator and likely a pass transistor and heat sink, and patch it
into the supply. This of course assumes that you have the radio
is for its utility, rather than collector value. I'm sure many
collectors would not want to change the radio in any way.
73, David K3KY