Control head problems with Spectra

[abrigno1]

The head on my spectra faded out slowely and now there is no display. Head works fine does volume mode etc and I can go to correct spot counting beeps. My original head that faded out is a HLN6075C SP07.

I have acqired a new HLN6337cChead. When I put it on the radio I get nothing. Not lights sounds etc. The wiring shows it to be nearly identical but the VF1 & VF2 signals are in the different places. What are the VF1 & VF2 signals for.

Any ideas on a fix??? I can find an old display and change out the vacuum fluorescent display to my bad head but that seems extreme. Also not sure if head is multi level board etc. The backup connector board the connects the head to the radio body could be changed out but not sure what number I need to chase.

Any help would be greatly appreciated. I am sure some of you have come across this before.

[Will]

Your original head is a SP and may contain some circuit modifications, and or other changes.
First is the 'other' control head have the same jumper settings?
Then check you control head's circuit board for leaking capacitor damage.

"What are the VF1 & VF2 signals for. " they were used with external display options, VF = vacuum fluorescent display. There should not be anything connected to those pins on the cable side.

[d119]

You can always transplant the inverter from the good control head to the failed control head. It's likely that the VFD is not so much the problem as the inverter module has likely failed. It's the funky looking multi-legged transformer on the connector side of the board.

[N4KVE]

The 6337 head is an advanced head. Assuming you're using the radio as a 1 piece front mount radio, the interconnect board between the control head & rear part must be changed to a HLN6285A board. However, in the Spectra section it shows how to upgrade your old board to the newer 6285 style. GARY N4KVE

[Will]

Gary is correct, check the interface connector board to see if it IS the later version.

transplant the inverter from the good control head to the failed control head. .

?? "inverter", no the inverter, as you call it is, not a replaceable module.

In fact the service manual warns to not even measure that circuit. You should have 35 to 40 volts DC OUTPUT at the 10uF capacitor near
IC 101the VF driver chip.

[abrigno1]

Thanks for inputs from all. We had some guys here that were Spectra wizards but they retired and moved and I am trying to learn about them so I can help the hams here. We have about 25-30 Spectras in our 900 MHz community.

My exitsting head is a HLN6075C SP07 with a HLN6285A back/connector board. The newer HLN6337 board with the HLN6285A board was dead and did not work. At this time I don't have a spectra manual but have that on the list to aquire. If not before, I'll look at Dayton.

Good news is that I have located two new heads that are on way. One is an HLN6075D SP07 and the other is a plain HLN6075. Both of these are in route and appear to be the best shot at trying to get this thing going again.

Another issue I have that is minor is the audio quality. We have many GTX here on 900MHz and the audio is very good. The Spectra sounds a little muffled. Easily understandable but slightly muffled compared to the GTX. The audio problem is down in the pile a little ways.