Danelectro Chicken Salad - Not modulating

[battery acid]

Hey there guys! I'm modding a Dano Chicken Salad for a friend, making it true bypass. Well, that part was very sucessfull, but I'm not getting any modulation. I did some tests, and when I short the base and the collector of the darlington that makes the lamp oscilate, it lights up, but when I don't do it by shorting it myself, the lamp stays off. Hope you guys can understand my english, it's late and I'm tired of messing with this little mofo

[battery acid]

I know it isn't cool to do this, but I'm messing with this circuit for days and I still don't have a clue. All I know is the lamp is working, but the LFO isn't, since the light isn't flashing. It just lights when I short the legs of the MPSA13... any help will be much appreciated

[Muthauzem]

Well.. In this case you should start by assuring that the transistors are not damaged.
From what I see from this schematic: (http://www.experimentalistsanonymous.com/diy/Schematics/Vibrato%20and%20Pitch%20Shift/Dan-Electro%20Chicken%20Salad.gif) the darlington pair is the oscilator. Try checking the other transistor, that actually turn the light on/off.

[Jaicen_solo]

Look at your bypass technique.
The chicken salad turns off the lamp in bypass, to save the batteries (yeah, I know, it's not even funny).

You need to find the cmos switch or whatever it is that is responsible, and mod it so the lamp stays on.

[battery acid]

Well.. In this case you should start by assuring that the transistors are not damaged.
From what I see from this schematic: (http://www.experimentalistsanonymous.com/diy/Schematics/Vibrato%20and%20Pitch%20Shift/Dan-Electro%20Chicken%20Salad.gif) the darlington pair is the oscilator. Try checking the other transistor, that actually turn the light on/off.

I'm a little lost here. The MPSA13 is the Darlington pair, isn't? and it's the only non-smd transistor on the board. There are two smd transistors on the other side of the board that seem to be in the darlington configuration too, but unlike the schematic posted, they aren't connected directly to any of the lamp's legs. The MPSA13 (the one that makes the lamp light up when i short it), in the other hand, is directly attached to it.

My english isn't very good, so, if you don't understand I can take some pictures and mark out the transistors as reference.

Look at your bypass technique.
The chicken salad turns off the lamp in bypass, to save the batteries (yeah, I know, it's not even funny).

You need to find the cmos switch or whatever it is that is responsible, and mod it so the lamp stays on.

I removed the cmos switching and true bypassed it using this http://4.bp.blogspot.com/-StOHXDg1MQ4/TYFLHfhTKfI/AAAAAAAAED0/s3c6kUzFWyI/s1600/Bypass.jpg as reference (it seems to be verified) - but I'll check it out!

Thank you guys

[petey twofinger]

did you mess with the trimpot at all ? that will stop it from working .

[danielzink]

Look at your bypass technique.
The chicken salad turns off the lamp in bypass, to save the batteries (yeah, I know, it's not even funny).

You need to find the cmos switch or whatever it is that is responsible, and mod it so the lamp stays on.

Actually no.

In the chicken salad the bulb is pulsing all the time. Which is exactly why the pedals were notorius for being battery eaters.

In the Cool Cat vibe - Danelectro thought it would be great to turn the bulb on and off at bypass - hence the delay when engaging a Cool Cat.

Having rehoused over 20 Chicken Salads I can say without hestitance that the bulb should always be pulsing when connected to 9V.



I hook at rate LED up to all my CS rehouses and you can watch the LED pulsing all the time.

You absolutely do NOT need the flip/flop board to make this work.

There is some other underlying issue.


Dan

[pinkjimiphoton]

hey, are you dan zink from dod?
if so, cool! like the later models you designed, wasn't crazy about the original ones.

that said, i must agree with petey...that trimmer will kill the pedal..the light will light up, the whole 9 vards, but if it's even somewhat "off" the whole pedal can stop working. on mine, i was pulling my hair out.. the trimmer is REALLY cheap, and in mine's case, i had to basically goop it with a little rubber cement to get it to "stay" where it needed to to function...the sweet spot isn't very large.

also seems to depend on which model..i've seen some with incandescent GOW lamps, and some with what looks like an led or something.

[petey twofinger]

i had initially  drilled a hole in the chassis so i could just adjust the trimmer with a jewelers screwdriver . later i had added hot glue to this hole because i cut in a pot on the trimmer , and merely opered the trimmer all the way up to mininum resisyance . 3 months , many many uses / taking it out elsewheres it stopped working . i had rushed , the hot glue wasnt set and had dripped down to the trimmer . removing the hot glue , resetting the trimmer it worked for a few . ultimately i found removing the trimmer all together and just using a outboard pot mounted in the battery compartment worked well . although it pulled its " i am not working now " trick again the other night . applying slight pressure on the input jack , pushing it closer towards the output made it work . i opened it up to see if i could notice anything , it worked , couldnt replicate the fault . its boxed and working again ... for now .

thing is , apart from the hot glue indecent , i was really carefull when operating , but , i guess that says a lot right there .

[danielzink]

hey, are you dan zink from dod?
if so, cool! like the later models you designed, wasn't crazy about the original ones.

that said, i must agree with petey...that trimmer will kill the pedal..the light will light up, the whole 9 vards, but if it's even somewhat "off" the whole pedal can stop working. on mine, i was pulling my hair out.. the trimmer is REALLY cheap, and in mine's case, i had to basically goop it with a little rubber cement to get it to "stay" where it needed to to function...the sweet spot isn't very large.

also seems to depend on which model..i've seen some with incandescent GOW lamps, and some with what looks like an led or something.

Unfortunately no....

I'm just Dan Zink.

A basement pedal hacker. 

[pinkjimiphoton]

pleasetameetcha!!! 

me too!!!!!

[battery acid]

Thanks guys, I'll check the trimpot, maybe it broke when I removed that red glue. I don't have the pedal in hands right now, but, is there any chance of this problem being generated due to a bad speed pot?

[battery acid]

Hey buddies! I was messing with the pedal today, after a short vacation, and it ended up being a bad trimpot! now it is working like charm! Thanks a bunch!

[pinkjimiphoton]

cool! yah, mine wouldn't work after i messed with the trimpot, when i finally got it going i dropped some rubber cement on it so it wouldn't move again!