MOTM

I just sent this to Paul, but maybe somebody on the list can help 
me out??

Despite all the "fragile" stickers, my SKB rack of modules was 
victim to some rather rough handling by Lufthansa -- poor thing 
is covered with massive dents! All of the modules check out fine 
though, except for the 320 LFO. It's range has become very 
narrow using the "RATE" dial. It's slowest rate seems to be 
about the same as the FASTEST rate on the 101. FMing the 320 
with the 300VCO at a low setting brings it down to a useable 
rate... 

Any ideas where to start trying to fix this? Unfortunately I left all 
the papers at home (trying to travel light and I still had to pay for 
excess baggage!) so if this is covered in the documentation, 
please forgive me... I looked it over and there's nothing obvious. 
All the connections seem to be in place and I don't see anyplace 
to trim this manually back there. Oh yeah, and I did give it some 
time to warm up, although usually it seems to take about a 
second to warm up ;-))

hopefully,
- Scott
(who was very happy to find an 800 EG under the Christmas tree 
this year!!)

hello all,

sorry to hear of your disaster - maybe it's a broken rate pot..?
if the lid of your skb got dented in just the wrong place, it could
certainly mess up the track of a pot

word of warning - though it's too late now - never air freight stuff in an
SKB ATA roadcase - that's why it's called a road case. image a big loaded
samsonite suitcase floating 20 feet in the air and then crashlanding square
in the middle of your pop up mixer case - but whatever you do - don't
imagine the big grin on the baggage handler's face - not with children in
the room :-)

if might look stupid - but you could buy some chipboard, cut two skb sized
squares, foam one side of each, then get six good cargo straps, and strap
that suit of armour in place over the exposed faces

cheers
paul b

>sorry to hear of your disaster - maybe it's a broken rate pot..?
>if the lid of your skb got dented in just the wrong place, it could
>certainly mess up the track of a pot

That seems likely, that it would be a moving part.

>word of warning - though it's too late now - never air freight stuff in an
>SKB ATA roadcase - that's why it's called a road case.

All cases named "ATA" should satisfy a set of standards set by the Air
Transport Association, otherwise the term becomes meaningless:

http://www.rootintl.com/html/calzone_ata__specifications.htm

Have you tried running voltage into the 1/volt oct jack to slow it down?  If
that works, and the FM works correctly, you have narrowed the list of
potential problems down to a very few.

Four things are summed together to control LFO rate.

1 - 1 / volt per octave input (through R80)
2 - FM input (reversing) through R4
3 - rate pot (through R5)
4 - (-) 15 VDC through resistor R6 (fixed)

It sounds to me like the negative voltage connection to the rate pot is
broken, or as Paul B. suggested, maybe the pot itself is open internally.
But somehow, it seems that the negative -15 volt is not part of that pot
circuit any longer.

Measure voltage from the wiper (pin 2) of the pot to ground. You should be
able to see a voltage range at pin 2 of -15 to +15 volts.  If my suspicion
is correct, you will see a range of only  from +15 to about +10.5 (if my
quick math is right).  Anyhow, it will be a much smaller range than normal
and skewed was toward the positive (or fast) side of the LFO range.

If the voltage is good at the pot wiper, then check the connections at both
ends of R5 and R6 for breakage (they are both 243K resistors near the left
top of  IC # TL074.  But, I am like Paul B. I think the likely candidate is
either the pot is broken internally, or the -15 volt connection is broken
where the pot solders to the PCB. Those are more likely candidates

That's my 2 cents from looking at the schematic.
Larry H

----- Original Message -----
From: scottgibbons23 <scott.gibbons@...>
though, except for the 320 LFO. It's range has become very
narrow using the "RATE" dial. It's slowest rate seems to be
about the same as the FASTEST rate on the 101. FMing the 320
with the 300VCO at a low setting brings it down to a useable
rate...

----- Original Message -----

From: <mark@...>
> All cases named "ATA" should satisfy a set of standards set by the Air
> Transport Association, otherwise the term becomes meaningless:

hello all,
thanks mark - you learn something every day - i'll check on that link when i
get back to work on monday
however, i've had it on good authority in the past from two UK pro-audio
shippers that SKB cases shouldn't be let anywhere near baggage handlers,
nevermind air freight handlers
i was impressed with the protection on the pop up mixer cases i got
recently, but i that large facia is a definite weak spot - but saying all
that accidents and freak occurances do happen all the time...

cheers
paul b

> It sounds to me like the negative voltage connection to the rate pot is
> broken, or as Paul B. suggested, maybe the pot itself is open internally.

Yeah, the rate pot was knocked lose. Just by flexing the board a little, it
made contact better and worked perfectly.

> word of warning - though it's too late now - never air freight stuff in an
> SKB ATA roadcase - that's why it's called a road case. image a big loaded

In theory, an ATA case with fragile stickers all over it should be
sufficient. Both SKB and Lufthansa say so anyway.

I've got a few more weeks before I fly again... Guess I'll have to construct
a
foamed crate to put the SKB in for the way home. I used to think that it was
one of Rock's excesses that the big names had their own jets. After having
done repairs on gear just about every single time I've traveled though, I'm
understanding that a private jet is probably more of a necessity.

thanks all,
- Scott