Vintage Lighting fixin vintage EDI SCRimmer modules

[goatiemon]

good day

l'm new to this forum
lurked a bit
but my equipment is all so old
l never had much to say.....

l'm trying to repair my dimmers
and l know there is a LOT of knowledge/experience
here

any way
l run
edi scrimmer packs, with analogue control (l run an LP2000)
3.6kw tdu 12-3

modules say tpi d-3

the packs look alot like
Westportlights units in this thread

l can get pics if it becomes useful


l have various distinct failures towhit:

two modules with a double black condition
another with only one black channel
another with a full on failure one one channel
another with a ghost-on (it glows all the time -- disrupts blackuots)on one channel

(l have perhapse a couple more, l have 3 of these units and one of them is loaned out at the moment)

an order of trouble shooting operations
probable causes of these particular malfunctions
any other help/information would be greatly appreciated

thanks in advance
goat

 

[dramatech]

good day

l'm new to this forum
lurked a bit
but my equipment is all so old
l never had much to say.....

l'm trying to repair my dimmers
and l know there is a LOT of knowledge/experience
here

any way
l run
edi scrimmer packs, with analogue control (l run an LP2000)
3.6kw tdu 12-3

modules say tpi d-3

the packs look alot like
Westportlights units in this thread

l can get pics if it becomes useful


l have various distinct failures towhit:

two modules with a double black condition
another with only one black channel
another with a full on failure one one channel
another with a ghost-on (it glows all the time -- disrupts blackuots)on one channel

(l have perhapse a couple more, l have 3 of these units and one of them is loaned out at the moment)

an order of trouble shooting operations
probable causes of these particular malfunctions
any other help/information would be greatly appreciated

thanks in advance
goat

A couple of months back there was some very detailed repair information for the scrimmer packs and dimmers. You might want to search the forum.

Tom Johnson

 

[JD]

Yes, the thread you listed in your first post is a good place to start. My first suspect would be dirty trim pots, which on that design can leave you full on or full off! Check those little fuses mounted on the modules, often found near the connector plate in the back. Bad caps (due to age) are also high on the list. The modules used mega-oversized SCRs, so they would be last on the list unless the rig got hit by lightning!

 

[goatiemon]

thanks
thats what l figured, for starters

btu l though l would make my own post, cuz the failure modes were rather different
(the dimmers in the other thread woudl go on, then flicker off)

any way
l'll check back in if l run into any problems

goat

 

[goatiemon]

so fiddlin with the trim pots and plugging/unplugging the connector helped
but l still have 3 problem modules

all light up when the test button is pressed
the problem follows the module (when plugged in different rack slots)

module "A"
ch1 works normally
ch2 is stuck on at 80% or so
(it responds to controller input by getting brighter)

module "B"
ch1 is dark
ch2 works but reaches full brightness at about 80 (on the controller) and then goes out if you try to take it further (to full)

module "C"
ch1 is stuck on at 10% or so (no change with controller)
ch2 also stuck at 10 ish but goes black if brought up

l havent tried swapping the board to a know good module with any of these
(not sure if it is worth doing?) partially because one of the modules dosnt have an edge connector!! the leads are soldered to the board

any thoughts or leads on these particular problems

thanks again
goat

(l am loading in a show tomorrow and lighting a festival this weekend, so l wont get to play with this for a few days)

 

[JD]

so fiddlin with the trim pots and plugging/unplugging the connector helped
but l still have 3 problem modules

all light up when the test button is pressed
the problem follows the module (when plugged in different rack slots)

module "A"
ch1 works normally
ch2 is stuck on at 80% or so
(it responds to controller input by getting brighter)

module "B"
ch1 is dark
ch2 works but reaches full brightness at about 80 (on the controller) and then goes out if you try to take it further (to full)

module "C"
ch1 is stuck on at 10% or so (no change with controller)
ch2 also stuck at 10 ish but goes black if brought up

l havent tried swapping the board to a know good module with any of these
(not sure if it is worth doing?) partially because one of the modules dosnt have an edge connector!! the leads are soldered to the board

any thoughts or leads on these particular problems

thanks again
goat

(l am loading in a show tomorrow and lighting a festival this weekend, so l wont get to play with this for a few days)

Almost all the problems you described are caused in the ramp generator circuit. There is a basic schematic posted on the other thread. There are two or three smaller caps involved with timing that may have either shifted in value or may have developed a leak resistance. If the ramp waveform is distorted, the control voltage may miss the ramp voltage at some point in the waveform, which causes the "blackout" at certain settings. Likewise, the distorted waveform will cause low end and high end setting to not be correct, or miss by a mile!

As for the module that is stuck on at 80%, a failed SCR will usually leave it on at 100%, so I suspect a failure in the opto-isolator circuit, or the routing diodes between it and the SCRs. Even in this case, a distorted ramp waveform, where all control voltages cross at the same point may be the problem.

If you disconnect the control cable (Jones plug on pack), do all the channels go out?

 

[goatiemon]

at least one channel is on no matter what
control cable or not
(board on or not)

just got back from a hetic festival gig at an abandoned ammusenemt park
with the worst/scariest power situation l have ever experienced
(which is another story)
which may or may not have caused problems beyond loosing power in the middle of a set...

l did alot of mid show repatching and module swapping and thigns

any way
my plan is to look things over
l'll post again if l discover any thing

re capping in the ramp generator circuit does sound like a likely fix for most of the modules

thansk again

goat

 

[goatiemon]

so l set up a little test grid
a instrument on every circuit and did soem testing

module A (ch 2 @ 80) ch 2 is on no matter what (with or with-out control cable)
(ch1 works normally)

module B (ch 1 dark ) ch 2 works, but with out control is on at 80

module C (both channels @10 ) are on a with or with out control cable too

module D (new one ch 1 @10 with out control, starts acting normal after you use it a bit, but once you unplug control it starts ghosting again

module E (another new one ch1 started out not working, then was slow to turn on (started at 50) then it started working normaly

hope that info helps the trouble shooting

as for recapping
l seem to have 2 different board layouts

though they seem to have the same number of caps
2 @.005
2@ .01
1@ .001p
1@ .002
and then the main filter which your schematic identifys as 220
but l can't seem to find a marking other than (4) - 16

ought l to replace them all?
any other trouble shootin l can do
(my multi meter tests capacitance, but only off the board)

muchimas gracias for all the help
goat

 

[goatiemon]

just plugged the modules back in after lookign at the boards
and now l have a dead slot
any module in it gets no test light and wont function

so now l get top open it up and look for the bad connection
any helpful hints would be appreciated
(but l imagine it is fairly self explanatory)

goat

 

[JD]

just plugged the modules back in after lookign at the boards
and now l have a dead slot
any module in it gets no test light and wont function

so now l get top open it up and look for the bad connection
any helpful hints would be appreciated
(but l imagine it is fairly self explanatory)

goat

Time for some pictures!

There are some variances between the generations, and options. Do your units use primary breakers (part of the frame) or just secondary breakers on the modules? The primary breakers are one per mod and can leave you with a dead slot if defective.

Some early EDI used pulse transformers and not opto-isolators. These circuits were quite quarrelsome. Since you have several "partial on" channels, and that was a common failure with them, I want to make sure we are not dealing with mods that old.

The larger cap (220uf) can go open-circuit when old and that can produce many problems. Old electrolytic can also start at a very low value, and start coming back up when warm, which describes some of the problems you have.

Pictures! pictures! pictures!

 

[FMEng]

Specifically, the capacitors most likely to fail from heat and age are electrolytics. You can generally tell an electrolytic because it'll have a value of 1 uF (microfarad) or more, up to as much as thousands of microfarads. Ceramics, which typically have a value of 0.1 uF or less, rarely fail.

Yes, the thread you listed in your first post is a good place to start. My first suspect would be dirty trim pots, which on that design can leave you full on or full off! Check those little fuses mounted on the modules, often found near the connector plate in the back. Bad caps (due to age) are also high on the list. The modules used mega-oversized SCRs, so they would be last on the list unless the rig got hit by lightning!

 

[WestportLights]

Hi goat,

I was between productions and haven't been here in a while, just now saw you post.

My condolences on your ailing unit. Be ready for some gray hair!

All kidding aside, I didn't see this mentioned anywhere.

Are you saying that all modules do not work in any bay? or 1 specific bay is dead?

Also, have you confirmed that it is the modules with the problems and not any of the bays? i.e. module A has same symptoms in bay 1, 2, 3, 4, 5, and 6? or module e only bad in bay 5 but module b works fine in bay 5.

 

[goatiemon]

so l got the slot fixed

turns out that the octal connector in the dimmer slot (not on the module)
had gotten pushed in
such that it wastn making contact with the module

not an easy place to get to.....

my units only have the secondary breakers

l'll get pics together asap
(l lack a camera)

2 of the modules look quite old
one of them dosnt even have an edge connector

wesportlights thaks for the condolences
l figure this is just what signed up for choosing to us equipment this old
(the problems follow their respective modules)

FMEng there is only one electrolytic cap on the board

thanks for everything
goat

 

[goatiemon]

ok here are some pics

they are from a borrowed phone/camera
and it was really hard to get decent photos

the first two are from the seemingly oldest module
(the one with out an edge connector)
know for the purposes of this thread as module A
(which has channel 2 stuck on at 80)

the rest are from a representative "newer" module (in this case C)
(stuck on @10 goes dark if brought up)


hope these pics are sufficient
if not let me know and l'll post soem more

thansk again

goat

More pictures at goatiemon's Album: vintage scrimmer repair .

 

[JD]

Besides the supply cap, there are 9 caps on the board. You listed the six disk caps in a prior post, but the epoxy dipped paper caps are a bigger problem. Replace the supply cap (big blue), the second most likely cap problem is the one between the right trim pot and the transistor. I remember that one to be .1 mfd, and is responsible for the ramp slope. Change these parts on your bad mods.

If you still have channels stuck on, remove Q1 and Q2. These two transistors drive the opto-isolators. The circuit can be powered up without them. If the channel is now dark, then the quad op-amp (14 pin package) may have failed. If the channel stays on, the opto-isolator or one of the SCRs may have failed.

 

[derekleffew]

As was said so eloquently in the other Scrimmer repair thread:

IMHO, this may not be the fastest or cheapest way to get your dimmer working. We call what you are doing "shotgun" troubleshooting--replace parts and hope it works. Without a proper extension harness to energize the dimmer outside the rack, a meter and/or oscilloscope, and a schematic in front of you--this may be a long and frustrating process. Oh, and you will also need a solder sucker to get the parts out without damaging the PCB.

I suggest that you get a quote from a reputable repair shop such as Lite-Trol. ...

goatiemon, perhaps it would behoove you to at least get an estimate from

EDI Service and Repair
Alan Child
Phone 503-781-7361
[email protected]
Electronics Diversified equipment

or one/some of the other vendors listed at Service and Repair Vendors - ControlBooth .

 

[goatiemon]

thnaks jd

l hadn't realized those were caps (l did wonder...)

derekleffew
l will call edi service
didn't know any such thing existed

at the same time
l like fixing things my self
learn more that way, can do it again, etc

also a hand full of caps, is likely to be a bit cheaper
thanks mailing dimmer modules to pay soem one else to trouble shoot/change caps

look into both options on the morrow

goat

 

[goatiemon]

in trying to source the epoxy dipped caps
l've run into a bit of confusion about the value

JD's schematic seems to say that they are .1 uf

but when l plug the color code
brown
black
yellow(it dosnt have an option for yellow in this position -- so l used orange)
white
red
into this calc
it tells me the value is 1uf
can some one help me resolve this dilemma

thanks
goat

 

[JD]

Like resistors, the yellow is in the multiplier band location. There is a goof in the calculator as it jumps from nF to uF.
Brown = 1
black = 0
yellow = followed by 4 zeros.
or 100,000 nF
divide by 1 million for uF = .1 uf

Color codes might be in the Wiki, but here are the rest anyway:
red =2
orange = 3
yellow = 4
green = 5
blue = 6
violet = 7
gray = 8
and white = 9

These colors hold true for resistors, capacitors, and some wiring harness. (such as the old ribbon cables.)
Good thing to commit to memory as I am astounded by how many other things in life use the same system! (Except TELCO, they came up with their own odd system!)
By the way, pF (picofarad) and nF are the same. Here is a better chart page:
http://electroschematics.com/5713/colour-coded-capacitor/

 

[goatiemon]

so l took one of the boards
(out of mod B)to my friend who works at west coast tube works (santa cruz)
and we used a cap checker
and what not looked at all the components
all the caps are fine

the opto isolaters read differently
but we aren't really sure what they should look like if working....

the dimmers and the module are in Oakland
(lack of space)
so l cant really do any thing else at the moment

know any good way to test the opto isolaters

or other bench top things to check out
(l'm working on getting a dimmer pack down here, but...)

goat