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



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