wavetek waveform generator model 75 no response :-(((

D

David O'Dell

Guest
Hey all,

Thanks in advance for any help on this. I'm a high school physics teacher and I came across this device in a surplus warehouse and I'm hoping to get it working if possible. It is a wavetek brand waveform generator model 75.

the device turns on but the LED display panel is all black blocks and no digits. I've read the manual and tried the reset procedure of hitting setup 3 times, then f2 and then f3 but there is no response even during this process. I have measured the signal from all of the outputs and no response.. I really hope this is a common problem and is fixable, this would be a very meaningful device for my students in our classroom.



has anyone had experience with this problem on this or a similar device before?

thanks!

dave
 
David O'Dell wrote:

Hey all,

Thanks in advance for any help on this. I'm a high school physics teacher and I came across this device in a surplus warehouse and I'm hoping to get it working if possible. It is a wavetek brand waveform generator model 75.

the device turns on but the LED display panel is all black blocks and no digits. I've read the manual and tried the reset procedure of hitting setup 3 times, then f2 and then f3 but there is no response even during this process. I have measured the signal from all of the outputs and no response.. I really hope this is a common problem and is fixable, this would be a very meaningful device for my students in our classroom.



has anyone had experience with this problem on this or a similar device before?

thanks!
There don't seem to be a service manual up front, I didn't fully look
Click to expand...

But what you describe sounds like bad caps, electrolytic types. Most
likely from sitting around and one in a critical area dried out.

Also, that unit could have a lithium cell in it for memory, some times
they get bad enough to where they hold down the start up process of a
diode isn't being used to isolate it.

I would take it apart and look it over..

Jamie
 
On Jun 3, 5:29 pm, "David O'Dell" <texasda...@gmail.com> wrote:
Hey all,

Thanks in advance for any help on this.  I'm a high school physics teacher and I came across this device in a surplus warehouse and I'm hoping to get it working if possible.  It is a wavetek brand waveform generator model 75.

the device turns on but the LED display panel is all black blocks and no digits.  I've read the manual and tried the reset procedure of hitting setup 3 times, then f2 and then f3 but there is no response even during this process.  I have measured the signal from all of the outputs and no response..  I really hope this is a common problem and is fixable, this would be a very meaningful device for my students in our classroom.

has anyone had experience with this problem on this or a similar device before?

thanks!

dave
Click to expand...
Do you have access to a voltmeter and an oscilloscope? I would
contact the manufacturer and explain to them that you are a teacher
and need some help in fixing one of their products for use in high
school classes and see what they offer to do. Tell them even a
schematic would help, but only if they don't seem very helpful.
 
Jamie wrote:
David O'Dell wrote:

Hey all,

Thanks in advance for any help on this. I'm a high school physics teacher and I came across this device in a surplus warehouse and I'm hoping to get it working if possible. It is a wavetek brand waveform generator model 75.

the device turns on but the LED display panel is all black blocks and no digits. I've read the manual and tried the reset procedure of hitting setup 3 times, then f2 and then f3 but there is no response even during this process. I have measured the signal from all of the outputs and no response.. I really hope this is a common problem and is fixable, this would be a very meaningful device for my students in our classroom.



has anyone had experience with this problem on this or a similar device before?

thanks!
There don't seem to be a service manual up front, I didn't fully look
Click to expand...

You didn't look at all. The first hit on Google provides the
manual:

<http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CDAQFjAA&url=ftp%3A%2F%2Fftp.rowland.org%2Fpub%2FEE-Lab%2FManuals%2FWavetek%2F75%2F75_man.pdf&ei=mk6tUa-1D-PG0gH7j4DAAQ&usg=AFQjCNHdCoJ9IroYOycz0NhZm0mfz2lmGw&sig2=cGuZTADipaNmQQ3v82SRRw>
 
David O'Dell wrote:
Hey all,

Thanks in advance for any help on this. I'm a high school physics teacher and I came across this device in a surplus warehouse and I'm hoping to get it working if possible. It is a wavetek brand waveform generator model 75.

the device turns on but the LED display panel is all black blocks and no digits. I've read the manual and tried the reset procedure of hitting setup 3 times, then f2 and then f3 but there is no response even during this process. I have measured the signal from all of the outputs and no response.. I really hope this is a common problem and is fixable, this would be a very meaningful device for my students in our classroom.

has anyone had experience with this problem on this or a similar device before?

thanks!

dave
Click to expand...


The manual shows a 16x2 LCD. (I posted a link to the service manual
in a different message) BTW, it is Wavetek Model 75 Arbitrary Waveform
Generator, which means you need to design the shape and amplitude you
want at the output. From the manual I found online, it was built around
1985.


The first thing I would do is look at the three outputs from the
power supply. +5, +15 and -15 volts. Is it a simple linear power
supply with a LM7805 three terminal regulator for the +5 VDC and a LM125
(or LM325A) IC regulator for the + & - 15 VDC supplies, so it will be
easy to test & repair.


It's also possible that the LCD has failed, due to age but most of
these are generic parts.


The unit is based on a 6303 MPU, which is the Hitachi version of the
Motorola 6803. It has a 27C256 EPROM with the firmware, and a 64 Kb
static RAM. It should be simple enough to troubleshoot.

BTW, there is a newsgroup specifically for test equipment questions:
news:sci.electronics.equipment
 
David O'Dell <texasdave2@gmail.com> wrote in message
news:0d37f3fd-e13e-4b8d-8789-da9fa3c7e849@googlegroups.com...
Hey all,

Thanks in advance for any help on this. I'm a high school physics teacher
and I came across this device in a surplus warehouse and I'm hoping to get
it working if possible. It is a wavetek brand waveform generator model 75.

the device turns on but the LED display panel is all black blocks and no
digits. I've read the manual and tried the reset procedure of hitting setup
3 times, then f2 and then f3 but there is no response even during this
process. I have measured the signal from all of the outputs and no
response.. I really hope this is a common problem and is fixable, this
would be a very meaningful device for my students in our classroom.



has anyone had experience with this problem on this or a similar device
before?

thanks!

dave

+++++

My only Wavetek generator , of that era, repair experience, was a shorted
22uF tantalum on a power rail and so a "dead" machine
 
"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in message
news:zJidnTIm1ckCzTDMnZ2dnUVZ_oednZ2d@earthlink.com...
Jamie wrote:

David O'Dell wrote:

Hey all,

Thanks in advance for any help on this. I'm a high school physics
teacher and I came across this device in a surplus warehouse and I'm
hoping to get it working if possible. It is a wavetek brand waveform
generator model 75.

the device turns on but the LED display panel is all black blocks and
no digits. I've read the manual and tried the reset procedure of
hitting setup 3 times, then f2 and then f3 but there is no response
even during this process. I have measured the signal from all of the
outputs and no response.. I really hope this is a common problem and
is fixable, this would be a very meaningful device for my students in
our classroom.



has anyone had experience with this problem on this or a similar device
before?

thanks!
There don't seem to be a service manual up front, I didn't fully look


You didn't look at all. The first hit on Google provides the
manual:

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CDAQFjAA&url=ftp%3A%2F%2Fftp.rowland.org%2Fpub%2FEE-Lab%2FManuals%2FWavetek%2F75%2F75_man.pdf&ei=mk6tUa-1D-PG0gH7j4DAAQ&usg=AFQjCNHdCoJ9IroYOycz0NhZm0mfz2lmGw&sig2=cGuZTADipaNmQQ3v82SRRw
Click to expand...
Having had a look at the manual that Michael has kindly provided the link
to, my very first step would be to check the main supply rails (+/-15v and
5v page 133 and 80 of the pdf) for level and noise, replace the lithium
battery, followed by - if that doesn't restore it - examining the operation
of the reset circuitry for the micro - see pages 4-14,15,16 (pdf 75 ++) and
pdf page 120 for the schematic of that section

Good luck with it. It looks a decent bit of equipment, functionally at
least, and I'm sure that working, it would be a useful asset to your
department.

Arfa
 
Hi
I've the same instrument.
Mine doesn't lit up at all.
Power supply is good but the problem should be in the logic circuit.
I'm looking for the service manual but i can't find it anymore at rowland website
linked by Michael.
Have you downloaded a copy of the manual before that was deleted from site?
In this case, can you send me a copy?
 
On 27/05/2014 10:17, gianluca.locri@gmail.com wrote:
Hi
I've the same instrument.
Mine doesn't lit up at all.
Power supply is good but the problem should be in the logic circuit.
I'm looking for the service manual but i can't find it anymore at rowland website
linked by Michael.
Have you downloaded a copy of the manual before that was deleted from site?
In this case, can you send me a copy?
Click to expand...

try archive.org
 
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