LTC1799 precision oscillator problems

[Simon Vactrol]

Hi i've just read the installation guide...excellent.
But something happen today while i was trying to pitch bend a keyboard(yamaha ps 1 "COIL") with my CB.CO.UK ltc:
1)i've built the ltc..no problem the guide is very detailed.
2)i've found the right voltage, 4.5V stable.
3)then with the out of the ltc i've managed to get the clock frequency change (pitch up) but after 30 second my ltc died!!
So i've made another one..And hooked it on another voltage point 3.8..but same question..dead

Should i cut the trace before the installation..or is just somethig can happen?..or???

Hope you can help me.

SV

[Circuitbenders]

hmmm, you really need an oscilloscope here to see if the LTC is actually outputting anything. i'd be very surprised if the LTC's are actually dead, unless you've somehow reversed the power inputs with a fairly large input voltage. If that was the case then it would never have worked at all. Are you sure you're not trying to run the PS1 at a clock rate that makes it crash? Try turning it on with the LTC pot set differently, and check that you definately have the LTC soldered in the correct way round.

It could be that what you're thinking is a steady voltage to power the LTC is in fact all over the place, but your multimeter isn't fast enough to register it, assuming you are using a multimeter. I take it the PS1 doesn't have a voltage regulator to source a steady 5v?

What voltage does the PS1 run on? If its over about 7.5v or so, you could always hook up your own 5v regulator.

If the coil is still in place when you are soldering in the LTC you may find that its all very unstable and you might need to just remove it completely.

[Simon Vactrol]

 I've checked both with an hand lens with led and light at the back too for full contrast , and yea! i use multimeter..strangely''i had the same result from both ltc...so is nothing concerning that..both same reaction like" smell of dead IC..strange indeed"" cos i was pretty sure was possible to pitch bend it.
PS1 runs on 6 C cells...and i'm not sure has a voltage regulator..current on board is 8.5 almost everywhere,,probably the main reason of the failure!!
...anyway i've just bought 2 more...but they gonna have a different destination....i'm bending a ps 1 just to experiment on few ideas:like the "the throaty high pass filter kind of distorsion"   and some other  random ideas i had those days...
i have a picture of the board on the component side if yo have the time to be curious.


SV

[Circuitbenders]

I've just split this topic into a new one.

thinking about it again, if you've built the LTC circuit correctly you should be able to run it on its own from any voltage source such as 3 x AA batteries or a regulated power supply. If you don't have a scope you can test if its working by listening at the output pin through some kind of amp or mixer, or even a pair of headphones might do it. A lot of the range will be outside of your hearing range, but you should be able to hear something at its lowest setting.

Having said that, if they smell burnt then they might well be dead, especially if they've been running on 8.5v

Post a picture of the board and we'll see if we can find 5v.

[Simon Vactrol]

Hi Paul here is the link for you to have a look at the circuitboard..hope i did it right

http://www.flickr.com/photos/58605885@N04/5376235960/#lightbox/

Let me know...




SV

[Circuitbenders]

what are you measuring relative to ground on pin 14 of the D4068UBC chip on the bottom left picture? Pin 7 will be ground and pin 14 will be the positive supply.
The datasheet is here http://pdf1.alldatasheet.com/datasheet-pdf/view/50857/FAIRCHILD/CD4069UBCM.html

Also what are you getting wherever the board is labelled VDD, like just above where it says 'master clock' on the top right picture?

It could be that one of those transistor shaped components is in fact a regulator in a transistor style case.

[Simon Vactrol]

Something happened while i was trying to sort things out and the drum is now disappeared!!...i could not be bothered to fix it!! that damn keyboard it has already given me too much trouble!!..Thanks anyway!!
I thing i've got it about "Why bother modding something when you could just get a better machine?"...
"i've learned the lesson"

Positive!

SV

[Circuitbenders]

"i've learned the lesson"

lol, sometimes its better to just walk away! 

[electoyd]

Simon, you quitter! i expected better from you    Find that broken drum part and fix it and there must be a reason that ltc ain't workin??  come on where's them electronic skills you've been honing,  you gonna let a little keyboard beat ya?  only jokin fuck it piece of shit keyboard, i always think if something causes you this many problems as your bending it, it's never gonna be reliable to use as a bent instrument in a set up.  Good to see you on the forum simon-take it easy now Ian