Details about B W D Mini-Lab Model 603B function generator power supply voltage amplifierSee original listing
For parts or not working
“See detailed description of test results in the listing text”
19 Aug, 2014 22:50:52 AEST
Brompton, SA, Australia
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|Condition:||For parts or not working
An item that does not function as intended and is not fully operational. This includes items that are defective in ways that render them difficult to use, items that require service or repair, or items missing essential components. See the seller’s listing for full details. See all condition definitions- opens in a new window or tab
|Seller Notes:||“See detailed description of test results in the listing text”|
b.w.d Mini-Lab Model 603B, includes function generator, regulated power supply and voltage/operational amplifier
I did find some issues with the amplifier section as it wasn't delivering the correct output. This is a minor issue with the Op-Amps which are easily to replace. I did insert a new one into a slot, and it seemed to work, however I didn't fully test this after that to confirm.
The function generator has had some significant changes done to it. The ramp generator was working and this fed into the 1st stage to produce the base Triangle wave to feed the three function outputs (ie. Square, Triangle and Sine waves).
Analysis of the circuit shows that several components are missing:
Changes to the board:
Square Wave - Works
Triangle Wave - not working
Looks to be missing the buffer stage between Stage 1 to the amplifier, alternatively R18 goes directly into the amplifier, which I don't think would work without the buffer impedance change. I copied the buffer design from the Issue 21 of the BWD 603B on a breadboard, and was able to produce the triangle wave output via the Function Generators amplifier.
Possible solution: Add an extra board and tap into the Stage 1 triangle output and input it into the Function Generator amplifier output
Sine Wave - not working
U100 and other components are missing. The board looks to
have had some changes to it to accommodate a square wave output only. I
couldn't get a sine wave output. Without the schematic I decided it would be
easier to build the circuit on a separate board and then tap it into the
amplifier output section.
Amplitude Modulation (AM Input) - Not working
FM input - Not tested
Call Tim with any questions 0419 363 992 or email me on firstname.lastname@example.org This item may be inspected by appointment at our office