Lexel 88 issue..... need help

[DreamBeamz]

I have a lexel 88. For the first time I tried to power it up at my
house which has 240volts

I got it to fire instantly but it was really bright. I tried to adjust
the current control but it did not adjust. I cut it off and tried to
cut it back on but the laser would only fire for a second and cut off,
its still really bright regaurdless of whats on the current control.
This laser has no light control just so you know. I tried another
current control board and it still does the same thing. Any ideas?

Thanks in advance

George

[Florian]

Hi,

Maybe your voltage for the regulator is out of range and the linear
regulator does not work (assuming you have the linear standard lexel 88
power supply). In this case the taps on the transformer need to be set
right.

You should measure the voltage drop over the regulator (I think you even can
monitor this by selecting "reg. volt." with the fron panel dial).

If this is ok, another reason could be a short circuit transistor in the
linear pass bank.

florian

"DreamBeamz" <Dream...@gmail.com> schrieb im Newsbeitrag
news:1133247608....@g47g2000cwa.googlegroups.com...

[STEVE ROBERTS]

> Maybe your voltage for the regulator is out of range and the linear
> regulator does not work (assuming you have the linear standard lexel 88
> power supply). In this case the taps on the transformer need to be set
> right.
>
> You should measure the voltage drop over the regulator (I think you even can
> monitor this by selecting "reg. volt." with the fron panel dial).
>
> If this is ok, another reason could be a short circuit transistor in the
> linear pass bank.
>
> florian

Florian is correct, either your tapped wrong or have a bad passbank
transistor. A thir possibility is a bad overcurrent limit , but since
you describe the start pulse as bright, that is unlikely.

A tap chart is located in Sam's FAQ under lexel 88

Tap Chart for Lexel-88 Power Supply
(This is basically the same for the Lexel-85.)
Buck/Boost Transformer

Measured Voltage Orange Wire Blue Wire Action
------------------------------------------------------
190-203 VAC TB2-1 TB2-3 Boost
203-215 VAC TB2-2 TB2-3 Boost
215-227 VAC TB2-1 TB2-1 Even
227-238 VAC TB2-2 TB2-1 Buck
238-245 VAC TB2-3 TB2-1 Buck

Note: Orange wire labeled "O" and blue wire labeled "B" on redrawn
schematic.

Filament Transformer

Turn on "Line" circuit breaker. Measure AC voltage between TP5 and TP6
on front panel. SWITCH OFF "Line" circuit breaker before changing
switch S10:

Voltage less than 116 VAC: Set S10 to position "A".
Voltage between 116 and 126 VAC: Set S10 to position "B".
Voltage more than 126 VAC: Set S10 to position "C".
If less than 108 or greater than 135, consult manufacturer.
Each tube has its own test sheet - use those settings instead if
available

If you give Lexel the tube serial number, I'm sure they could look up
your cathode settings for you.

Dont run that tube much more then 15-16 amps at first, we need to
dtermine how healthy it is before you crank it up.

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