On Mar 12, 5:17*pm, Winston wrote:
klem kedidelhopper wrote:
On Mar 12, 11:59 am, klem
(...)
Well I couldn't resist, so to take this a bit further I checked the
power supply supplied with the radio. It is rated at 9.00V .200A. The
no load voltage is 9.50V. With it connected to the radio and with the
radio playing softly its output drops to 9.25V. In looking at the
schematic again and rereading the statement a few more times I now do
believe that in spite of the ambiguity, the original intention was to
supply 7.50 V to *the battery terminals, however reference all
adjustments and voltages to the positive side of C59, (system ground).
So I did that and set the bias on FM to -1.18V. (AF126 I E) I then
recorded the following voltages:
Here, I added a Vnom column.
* * * * * * * Voltage readings
* * Test point * * * * * Radio working: * *Nominal V
------------------- * * * * ---------- * * -----------
* * E. AF178 * * * * * * * *-1.15V * * * * * * * * -0.85
* * B. AF178 * * * * * * * *-1.48V * * * * -1.15
* * E. AF124 * * * * * * * *-1.14V * * * * -0.94
* * B. AF124 * * * * * * * *-1.37V * * * * -1.12
* * E. AF121 * * * * * * * *-0.90V * * * * -0.85 (MW) -0.60 (FM)
* * B. AF121 * * * * * * * *-1.24V * * * * -1.05 (MW) -0.95 (FM)
* * E. AF126 (1) * * * * * -1.18V * * * * *-1.18 (MW) -1.15 (FM)
* * B. AF126 (1) * * * * * -1.47V * * * * *-1.45 (MW) -1.4 (FM)
* * E. AF126 (II) * * * * * -1.14V * * * * -1.05 (MW) -1.0 (FM)
* * B. AF126 (II) * * * * * -1.34V * * * * -1.33 (MW) -1.0 (FM)
The *voltage across C59 is 6.65V
You are testing at Vrail = 6.65 V?
Grundig says "don't bother warming up the VTVM unless
Vrail ==7.5 V" *( I heard them. *Really I did. *
So now although the radio has been working fine on both AM and FM, I
notice that the first two stages are reading a bit high. I wonder if I
may have another leaky cap. I was looking at possibly C12, C19 and
C32.
The little 'K' symbol next to these three apparently
denotes a ceramic cap. These 500 V units could become
extremely leaky at 2 V I suppose.
I wouldn't bet that way, however.
There are lots more things that need your attention more
than your beloved radio. *Personally, I think that at this
rate, in another 30 days, you will become borderline
obsessive. *
My advice: Button it up and listen to it while doing one or mo
* * * * Clean or replace the sacrificial anode in your water heater
* * * * Do an oil change on your car
* * * * Flush and fill your car radiator
* * * * Rotate your tires
* * * * Replace the transmission fluid in your car
* * * * (Clean your funnel and flush with clean ATF first!)
* * * * Grab a basket and fill it with stuff from the back seat
* * * * and trunk. *Neatly put away, toss or donate the contents
* * * * of the basket.
* * * * Shampoo car carpets
* * * * Diagnose that rattle in your clothes dryer
* * * * Vacuum out your dryer exhaust vent
* * * * Clean your gutters
* * * * Replace clogged rafter end vents with new ones
* * * * Replace the nasty 'wiring' job in the garage with
* * * * real Romex or conduit as code permits.
* * * * Install a chimney - mount 'Over The Air' antenna and cancel
* * * * your cable TV subscription
* * * * Scavenge stuff out of one room or garage that you
* * * * honestly will never need and give it to your local
* * * * Freecycler
* * * * Buy a little microcontroller board and teach yourself
* * * * assembly language. *Make a robot.
* * * * etc. etc. *
--Winston
Wow! I'll never complain about my wife nagging me again. I think
you've covered everything. Lenny