Elegost said:Can someone please repost the build manual, and schematic?
The dropbox link above is dead. I want to see the calibration procedure.
I would really appreciate it!
a temporary load resistor (240R ... 1K) will show, if the regulator will behave correctly.ratty_7 said:...My -12VDC reads -19VDC ...
If you ever powered your device with the swapped places regulators, the 79xx won't survive this polarity reversed voltage feed, so it needs to get exchanged.I have to admit I accidentally put the regulators 7912 and 7812 in the wrong places then corrected them. Would this have caused a fault in a cap or something...???? Mike from Oz
as already said, 'a temporary load resistor (240R ... 1K) will show, if the regulator will behave correctly.'ratty_7 said:Hi Harpo,
Thanks for your quick reply.
I have replaced the 7912 and the 7812 with a new ones and put them in the right places, but I am still getting -19DCV, when it should be -12VDC
All other voltages ok... Mike
mattmartin831 said:I want to buy the SB4000 board and front panel but I don't think it will be able to mount onto my par-metal 1U rack case. Can someone please inform me what is a compatible rack chassis? Will it be able to mount onto the circuit specialists 1U rack?
wave said:I used a Par-Metal case when i built mine...
Harpo said:as already said, 'a temporary load resistor (240R ... 1K) will show, if the regulator will behave correctly.'
Without the rest of the circuit connected, the voltage regulator sees no load. The 79xx ones are a little more picky than the other. Just place a temporary resistor in range 240R up to 1K ohm for a 12...50mA load between the 0V and -12VDC connection (or across C151 or C152 for the same effect) in order to check if the vreg will behave correctly with load connected.
Harpo said:as already said, 'a temporary load resistor (240R ... 1K) will show, if the regulator will behave correctly.'
Without the rest of the circuit connected, the voltage regulator sees no load. The 79xx ones are a little more picky than the other. Just place a temporary resistor in range 240R up to 1K ohm for a 12...50mA load between the 0V and -12VDC connection (or across C151 or C152 for the same effect) in order to check if the vreg will behave correctly with load connected.
You already read my reply #1117 from pg.56 ? Pg.62 might be useful as well.ratty_7 said:Hi Harpo
I have a problem with calibration step 2.
1. I have put a 1k test tone at -5.5db =1.228 left ch to -5.5db - 1.236 right ch into the unit. The outputs back into the DAW.
2. I tried to adjust VR 1 and 2 but both adjustments have NO effect on either channel in the DAW ...any clues ..?
3. I then tried the alternative method using my Fluke True RMS meter and I was astounded that the left output ch read 1.224 AC volts and the right ch a whopping 34 volts AC ...???
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