Pure Evoke-3 radio

[MikeVou]

I have seen that there are Pure radio owners discussing problems on this forum, and I wonder if any of them can help me.
The display on my 10 year-old Pure Evoke-3 has gone very dim – only just readable in strong light even with the software Brightness setting at maximum. Since the backlight brightness is actually adjustable (from ‘almost invisible’ to ‘just about readable in good light’), it seems like the voltage to the backlight is low – possibly a feed resistor gone high in value or a faulty voltage regulator. Pure are notorious for their disinterest in support with service information, so can anyone answer these questions –

1. The display board seems to be held captive by the three control knobs after the pcb mounting screws are removed. The amount of force needed to remove them from their shafts seems to be huge. Is it safe/normal to just pull them as hard as necessary to remove – I’m afraid of damaging the switch mechanisms or destroying the knobs with the force needed.

2. Can anyone help with locating the backlight power supply components when I’ve removed the display pcb? Also the correct feed voltage for the backlight, and the voltage feed pins on the display?

 

[OXAUDIO]

Sorry I didn't see this thread sooner. The knobs are held in place by some kind of tape over the ends of the shafts and the only way I've found to remove them, is by gently prising whilst pulling. An old dodge was to use a length of nylon drive cord or something similar wound around the rear of a knob (behind the actual knob of course, then pulling the ends of the cord. Not tried that with a PURE radio, but it might work. Two of the three controls are held in place by nuts & washers. Once the knobs are off the nuts can easily be undone with a suitable diameter nut spanner or socket. Two different sized nuts are used. One thing of which to be aware is that the display is connected to the board via a ribbon cable inserted into a latched socket below which a rubbery pad is stuck. The pad must be carefully peeled back and the ribbon unplugged before the PCB can be removed. I don't know the voltage of the backlight, and have never made notes as to the voltages on the display pins so cannot help with that. At the time of writing this I am trying to source a replacement display for an Evoke 3. PURE of course won't supply any parts, but I spoke to someone at their technical dept. this afternoon, and was quoted £60.00 for a repair to this model. PURE can be contacted on 0845 1489001, during U.K. office hours, by the way.

 

[MikeVou]

Thanks for taking the trouble to reply. I did solve the problem in the end - much as you suggest - a very thin screwdriver blade is able to reach in and behind the knobs to lever them off - helped by a bit of pulling as well, Pulling alone - even with padding and pliers - doesn't seem to shift them at all (I never worked out why). I posted some photos of the process on original thread.

Thanks again.

 

[OXAUDIO]

Hopefully my thread will assist other members needing to dismantle PURE radios generally, and Evokes in particular!

 

[EFS]

To the original poster, I have a similar problem with an Evoke 3 and was wondering whether you had found the source of your particular problem. I haven't taken the front panel PCB off yet, but the voltage between the red and black wires that disappear into a huge blob of hot-glue seems to vary with back light level and I was wondering if that was the drive voltage? There's an SMD transistor marked 1F connected to the black lead, but I don't know whether this is a bipolar device or an FET (the smd markings websites list both.)

Any advice welcome.