PING STEVE ROBERTS
DreamBeamz
my lexel 88 with an ohm meter if the problem was not fixed, it wasnt
fixed but I have just been extremely busy to worry about it. The cause
of the damage is most likely me not changing those settings but now my
laser will only work if I find around 218 vac. It wont work below or
above even after adjusting the settings. Your help on this would be
greatly appreciated.
Thank you,
George
"If the tap setting doesnt correct the overcurrent shutdown, post here
again and we will walk you through a passbank check with a Ohm meter.
Steve Roberts"
ice juicy
STEVE ROBERTS
ranges of ohms scales, but preferable one that doest autorange.
A copy of the 88 schematic from sam's faq. a Amp clamp for measuring
cathode current if possible. Get the psu up on a work table where you
can get at the passbank easily and a LBT or other transistor checker
if possible. The LBT seems to be ideal for testing
control card transistor function. The smaller of the two lexel
passbank driver transistors tends to be leaky and the classic voltmeter
test doesnt hack it, you need to either pass current through it or
measure Hfe, so the LBT is very useful. IF you have one on your
bench, a CURRENT LIMITED (set for 100 mA) 0-30 V supply is very
useful for testing lexel control cards.
http://www.web-tronics.com/lilbittytester.html
http://www.action-electronics.com/lbt.htm
inital conditions for testing
transformer set to correct taps
water flow on
line voltage connected
autostart switch off (or autostart glass relay removed)
breaker on
cathode NOT lit.
Use a battery powered, isolated voltameter, do NOT use a older style
line powered DMM.
What is your AC line voltage when unloaded?
What is your AC control voltage reading at ?
(main breaker on, start not pressed)
Let me know, Steve
DreamBeamz
appreciated
I will setup the power supply and laser on my bench tomarrow after
work. I have ordered the LBT, I have a fluke 3 which does manual mode i
will use at the multimeter and I have another fluke with the amp clamp.
I do not have a current limited power supply except the one I use for
testing up to 3 watt 808nm diodes
I went back and read the original post along with all of the other
replies. One thing I was not clear, this laser used to work for me, at
several different venues including my house and every other place with
voltages ranging from 206 to 245 vac. I just didnt know about the S10
switch on the front which is probably what led to this lasers demise.
Also keep in mind I have several lexel spare parts to include a lexel
75 power supply as well as a lexel 95 power supply.
Please check back anytime after 8pm EST 10/26/06
Thanks again
STEVE ROBERTS
Steve
DreamBeamz
S10 set at C
Orange set on 1
Blue on 2
water flow on
--check
line voltage connected
--check
autostart switch off (or autostart glass relay removed)
--I dont know which is the relay so how about just getting the voltage
during its warmup before the start
breaker on
--check
cathode NOT lit.
--check
Use a battery powered, isolated voltameter, do NOT use a older style
line powered DMM.
--check
What is your AC line voltage when unloaded?
--126.4 assuming what you meant is during the power supplies warm up
but before start
What is your AC control voltage reading at ?
(main breaker on, start not pressed)
--127.3
STEVE ROBERTS
Steve
STEVE ROBERTS
>
> autostart switch off (or autostart glass relay removed)
> --I dont know which is the relay so how about just getting the voltage
> during its warmup before the start
one glass tube (usually marked K4) has 11NO30 on it, thats the cathode
warmup, the other glass tube is the autostart (a one second delay
marked like 110NO1) for a medical system, you can pull autostart and
the system will still run, but for troubleshooting you want it to time
in at 30 seconds but not light the tube.
Steve
DreamBeamz
I also found the relay and it does not attempt to autostart anymore
On Oct 26, 6:24 pm, "STEVE ROBERTS" <o...@uakron.edu> wrote:
> check
>
>
>
> > autostart switch off (or autostart glass relay removed)
> > --I dont know which is the relay so how about just getting the voltage
> > during its warmup before the startone glass tube (usually marked K4) has 11NO30 on it, thats the cathode
STEVE ROBERTS
I'm at the hospital with my mom, more to come monday evening.
start with the current control card, test all the npns and pnps out of
circuit with the LBT
watch for leaky transistors in the 3 transistor cicruit that makes the
- volts.
Steve
DreamBeamz
time on responce, hope all is well with your mother
DreamBeamz
current control card. I downloaded the spec sheets for the 6531 and
6534 transistors to make sure I had the correct collector, base and
emmiter pins
All tested fine and here is a simple photo displaying which tested as
what
http://www.dreambeamz.com/lexel/DSC02188.JPG
Also I forgot to mention, one time back last year when I was trying to
get it to fire, the resistor that I have circled in red in the picture
below blew apart. I had since replaced it.
http://www.dreambeamz.com/lexel/DSC02178s.JPG
> > Steve- Hide quoted text -- Show quoted text -
STEVE ROBERTS
> Also I forgot to mention, one time back last year when I was trying to
> get it to fire, the resistor that I have circled in red in the picture
> below blew apart. I had since replaced it.
> http://www.dreambeamz.com/lexel/DSC02178s.JPG
Circled in red is a Diode, and its one that protects the circuitry from
reverse voltage.
since those almost never blow, thats interesting, I'll have to think
about that.
shoot a picture of the component/wiring side of the passbank, email it
to me at osr@ o-hir-o- .net
(remove the dashes and small R oscar sierra romeo @ oscar hotel
india oscar dot net)
and I'll label the test points.and send it back to you.
I'll also send it to sam for the FAQ
Steve
DreamBeamz
if you did not get them
On Nov 1, 3:52 pm, "STEVE ROBERTS" <o...@uakron.edu> wrote:
> > Also I forgot to mention, one time back last year when I was trying to
> > get it to fire, the resistor that I have circled in red in the picture
> > below blew apart. I had since replaced it.
> >http://www.dreambeamz.com/lexel/DSC02178s.JPGCircled in red is a Diode, and its one that protects the circuitry from
STEVE ROBERTS
look at the picture, you should see the labled collector rail, and a
base rail, but note each transistor gets its own emitter resistor. One
end of the emitter resistors gets a common rail, and the other is a
junction between the transistor emitter pin and the emitter resistor,
that junction is you measuring point for easch passbank transistor.
When you hook up the ohm meter the bias netowrk will generate just
enough base current to bias the good transistors into conduction. You
want to measure from the collector rail to the junction between the
emitter and emitter degeneration resistors which are the big gold
colored aluminum resistors in the emitter of each passbank transistor.
Put the meter on low ohms, turn off the power to the laser, pull the
line plug, bleed the change off everything capacitive and hook the
meter red lead to the collector rail and move the black lead from
emitter resistor junction to emitter resistor junction. . eventually
you should see a pattern, it will be something like 16 ohms, 16 ohms,
16.1 ohms, 15.9 ohms, 16 ohms, 0 ohms, 16 ohms 16 ohms . The o ohm
junction is the bad shorted transistor. You may also see a open one,
with a infinate reading, but this is rare. You may have to change ohms
ranges till you see a good pattern. In rare cases you may need to
reverse the meter leads or try another meter as some (not very many)
meters use AC for ohms measurements. The shorted transistor can pull
the base lead down and cause the laser to only run over a narrow range,
or not run at all.
To test the 2 passbank drive transistors, carefully make a drawing of
what wire is soldered to the base and emitter leads , then desolder
them and use LBT. Do one at a time to avoid confusion, Make sure you
flip the LBT npn/pnp bias switch to make sure they are not shorted, ie
a reverse biased transistor should in most cases act like a good diode
and only conduct one way. Big transistors fail shorted in most cases.
LBT finds this by conduction on both NPN and PNP settings.
Steve
DreamBeamz
power subsystem diagram. I have found that Q10 on the linear pass bank
is faulty with 0 ohm reading. Both Q1 and Q2 read good when out of
circuit testing with LBT. My next question, aside from taking one out
of another power supply. Where can I get a replacement for the Q10
numbers on it are as follows:
IR 430
8132
I could not find a reference or match at any of the sites i use.
STEVE ROBERTS
DreamBeamz wrote:
> I did not get your picture but using what you typed below and sams
> power subsystem diagram. I have found that Q10 on the linear pass bank
> is faulty with 0 ohm reading. Both Q1 and Q2 read good when out of
> circuit testing with LBT. My next question, aside from taking one out
> of another power supply. Where can I get a replacement for the Q10
> numbers on it are as follows:
> IR 430
> 8132
its a DTS430, 2n6259 will work. two ways to go about this. I can sell
you a used 430, basically 3$ and shipping, so you have matched sets, or
you call go over on ebay and buy a whole coherent passbank from Dean
Glassburn. Usually we dont go doing a round robin in a passbank with
different part numbers and even different lot numbers, but a 2N6259
will work fine. in the picture, one other 430 is clipped outta the
circuit, so you should replace him too.
As long as you have a pile of spares, you can mix and match to some
extent.
Deans got the deal of the year, a 20$ buy it now for a whole coherent
passbank. So go search for seller nitelite.
Steve
DreamBeamz
circuit. Also, the coherent passbank dean has, would it work. I looked
at the part numbers on my lexel 75 power supply and they were not even
the same. E-mail me george@ my u-r-l- listed in my link above.com I
would like to purchase parts from you
STEVE ROBERTS
Steve