Synthesizer not found error

[g3xig]

Hi All,
I've just finished assembling and configuring V2 of the Minitiouner, but on running the "Check MiniTioune Driver and Filters V0.3a" utility, I have hit a snag which I haven't been able to resolve. All tests result in a 'green light' except for the Synthesizer detection test which repeatedly reports - 'Synthesizer not found'.
All voltages at the regulators check out correctly,
the D2XX drivers installed correctly,
the LAVfilters CODECS installed ok,
the "Install_usrc_ax_winXP" program ran successfully,
the USB cable is the Lindy Cromo type specified and
I'm using Win7 starter on an Asus Netbook with a USB 2.0 port.

Could this indicate that the NIM is partially defective or incompletely configured in some way?

Many thanks for any suggestions as to what might be going on!
Clive.

[g0mjw]

Are you sure the 3.3V supply is getting to the tuner? Check it on the pin. Its possible the tuner isn't working but not seen that before.

Mike

[g3xig]

Hi Mike,

Thanks for your suggestion. I checked the voltages at the pins of the tuner and was puzzled to see 1.1V (as expected) and 2.6V rather than 3.3V. Following the supply line back to the power source, I discovered that the 12V supply had folded back to 3.5V, too little for the sm regulator to operate correctly. It seems that the switch-on surge current drawn from the PSU had caused its output to fold back. Removing the link J2, powering-up the PSU, then replacing the link prevented this and allowed the supply voltage to stabilise correctly, after which the tuner passed all tests with flying colours!

What seems rather remarkable, is the fact that the tuner and USB interface operated at all with such an out-of-spec supply!

Thanks again for your help,
Clive.

[g0mjw]

Hi Mike,

Thanks for your suggestion. I checked the voltages at the pins of the tuner and was puzzled to see 1.1V (as expected) and 2.6V rather than 3.3V. Following the supply line back to the power source, I discovered that the 12V supply had folded back to 3.5V, too little for the sm regulator to operate correctly. It seems that the switch-on surge current drawn from the PSU had caused its output to fold back. Removing the link J2, powering-up the PSU, then replacing the link prevented this and allowed the supply voltage to stabilise correctly, after which the tuner passed all tests with flying colours!

What seems rather remarkable, is the fact that the tuner and USB interface operated at all with such an out-of-spec supply!

Thanks again for your help,
Clive.

That's good news - and one to note in case anyone else has the same issue. There is a lot of capacitance to charge and perhaps we need to think about anti-surge mods. I am not surprised the digital circuits were OK, the core voltage is 1.1V and was OK, the 3,3V is I think mostly for IO, the maximum current is only 40mA, so while a bit out of spec (minimum 2.97V) it probably would work.

For reference - the maximum tuner current is about 600mA and maximum 1.1V digital current is 400mA. These are all coming from the 4V supply. I did consider if the unit could be USB powered but its a bit too much. In practice, the currents are quite a bit less.

Mike