Delco Wonderbar Mystery

It was called "The Twilight Sentinel" it also incorporated a auto-dimming feature., and a timer that kept either the right, or left headlight and turn light on the same side lit for a short time after you shut your Cadillac down to light your want to the door.

[DavGoodlin]

I changed the 100 pf red-block mica capacitor, which was right under the PC board but I have the motor issue yet.
It seems frozen or stuck and looks like its really packed in there. I'll try to access it somehow.

[Gregb]

The motor in mine made a lot of noise and seemed to be slow. I was able to get a couple drops of oil into the bearing on the output shaft and that fixed it right up.

Gregb

[philcophan]

I could be full of it, since I haven't touched a Wonderbar for at least 40 years, BUT, if I recall, the return was by a solenoid and the drive was provided by a spring. (You do need a decent power source to activate the solenoid, if I recall) Cleaning and sparse lubrication may do it, but don't over do it as lube tends to collect scuz....

Jim

[Gregb]

The earlier ones were like you describe, my 53 Buick had the solenoid and spring. The later ones like this one have a motor.

Gregb

[DavGoodlin]

Originally Posted by philcophan

I could be full of it, since I haven't touched a Wonderbar for at least 40 years, BUT, if I recall, the return was by a solenoid and the drive was provided by a spring. (You do need a decent power source to activate the solenoid, if I recall) Cleaning and sparse lubrication may do it, but don't over do it as lube tends to collect scuz....

Jim

Well, that was it!, Thanks Greg - a few drops of oil on the worm drive and holding the radio in a way it runs into the motor did the trick. I also assumed these units function as if there is a hold-in contact and the bar is pressed only momentarily, but that is not the case. You need to press and hold the "wonder bar" UNTIL it advances to the next strong station, last night it was consistently stopping right at KYW 1060 and 2-3 others.

That motor is pretty small but draws about 3.2 amps when initial power is applied and drops to 0.5 amps when advancing the tuner, which it does now. That taxes my bench supply and voltage drops to 6 upon starting the motor, but it does work now.

I can see how useful this function was; All the presets are normally set for your area, then you take a road trip and have to twist the knob. How much better it was just to push a bar in and have it stop pretty close, if not spot-on, to the next powerful station. Pretty helpful in the days when distracted driving was to be avoided

[Gregb]

Hey Dave:
Something is still not right, you should be able to just push and release the button and it will search to the next station. You don't have to hold the button.

Gregb

[DavGoodlin]

Originally Posted by Gregb

Hey Dave:
Something is still not right, you should be able to just push and release the button and it will search to the next station. You don't have to hold the button.

Gregb

Its working now, just my power supply's poor regulation. On a car battery its performing just like it should - Thanks!

[Gregb]

Sounds good Dave. I don't know how much car radio work you do but Parts Express has a 6-15 volt 22 Amp regulated and fan cooled power supply for under $200. I bought one and it works great and has more than enough kick for any car radio I have come across.

Gregb

[Electronic M]

Another trick is to get a used car battery charger and a 25V 2200uF capacitor to wire in parallel with it...Mine can do 20A before the fuse blows, and with the cap is clean enough to power a radio.

[NoPegs]

Originally Posted by Electronic M

Another trick is to get a used car battery charger and a 25V 2200uF capacitor to wire in parallel with it...Mine can do 20A before the fuse blows, and with the cap is clean enough to power a radio.

A note for anyone following this handy tip: Make sure that the "used" charger you're buying is of the "boatanchor" variety. The newer, lighter SMPS based chargers need some modification before being used as PSUs, and need serious filtering/chokes to be used for AM radios. "Boatanchor" types just need a filter cap and maybe punch a few holes and drop a fan into the case so they don't buzz and drive you insane after warming up. If you luck into one that has an "engine start" option you can build a small scale spot-welder. (These are usually the on-wheels variety, bigger than a "boatanchor" but I can't call them anchors because they're inherently mobile!)


If you find an identical pair of 10A (Heavy-Duty) or 20A (Marine/RV) chargers, you can extract the transformers and back-to-back them for a 130VA or 275VA poor-man's isolation transformer. Alternatively you could run 66 or 133 12AU7s in parallell.

[Electronic M]

Originally Posted by NoPegs

A note for anyone following this handy tip: Make sure that the "used" charger you're buying is of the "boatanchor" variety. The newer, lighter SMPS based chargers need some modification before being used as PSUs, and need serious filtering/chokes to be used for AM radios. "Boatanchor" types just need a filter cap and maybe punch a few holes and drop a fan into the case so they don't buzz and drive you insane after warming up. If you luck into one that has an "engine start" option you can build a small scale spot-welder. (These are usually the on-wheels variety, bigger than a "boatanchor" but I can't call them anchors because they're inherently mobile!)


If you find an identical pair of 10A (Heavy-Duty) or 20A (Marine/RV) chargers, you can extract the transformers and back-to-back them for a 130VA or 275VA poor-man's isolation transformer. Alternatively you could run 66 or 133 12AU7s in parallell.

Good point. Mine is a Triplite brand line transformer and diode type unit that also can function as a 550W inverter.
If it ever dies it is heavy and small enough to make a decent anchor. LOL.

It actually has enough nuts to start my 4 cyllinder liquid cooled riding mower when the battery is too weak to convince the starter motor to budge it's self.

[Gregb]

I used to use the battery charger and cap trick and they work ok for the standard 12 volt radios. The problem I was running into was 6 volt stuff and 12 volt tube wonderbar radios, the wonderbars take a pretty good surge of power to work properly and I found the battery charger would sag to much and not allow it to work properly.

Gregb

[Electronic M]

Why not plug the supply into a variac and while measuring the charger output crank it down to 6V for the 6V radios.

[Gregb]

I guess I could have done that but I do a LOT of car radio repairs and I needed something reliable on the bench and ready to go when I needed it. I don't have the time to coble something together every time I needed it. I also find a good regulated supply gives much better results.

Gregb