Messages

Hello, I have a Hohner Electra which I'll be servicing soon. Mine is an early model without the tremolo/vibrato and I was wondering if anyone has any info, photos or a scheamtic for this part of the circuit? You can find the original schematic attached.
Thanks!

So it turns out M5 self tapping screws fit the original U clips perfectly. I used these 35mm ones cut down a bit with a hacksaw: Phillips Hex Washer Self Tapping Screws, M5 x 35mm

I also used rubber washers in place of the plastic washers below the harp which has improved sustain immensely and reduced most of the weird overtones. I put 3 at the front and 4 at the back in the bass section, and replaced the metal washers on top with rubber ones. I also used some below the pickup covers to tame other resonances.

Just waiting on some more washers to arrive to finish the treble section, but it's already singing way more than it ever has done!

Thanks! I'll have a listen to the vibrato circuit once I've finished the acoustic set up and transistor/cap swaps, but I think it's pretty clean at the moment.

One thing I do have is noise when powering off (an audible thump on the speakers and possibly on the DI). Not sure if the recap will fix this, or if something in line with the speakers or a resistor/cap to ground on the speaker line will eliminate this?

Thanks velo-hobo! I've since disassembled further and ordered a few bits to replace the original screws (new M5 self tapping screws and "spire clips" in the post).

The service manual suggests paper keybed shims for the harp to fix dull/quickly decaying notes, and while this works a bit, I've found 1mm rubber washers are a lot better! I've also added these between the harp and pickup shield to remove some acoustic rattles I had. Hopefully the harp will only be ~0.5mm higher after reattaching everything so I won't have to adjust the letoff much.

It's amazing how much the resonance of particular notes are affected by the harp screws though! 1/4 turn makes a huge amount of difference.

This is some amazing work! It would be wonderful to hear what it sounds like

Does anyone know what size/thread these screws are on my Wurli 200A? (The middle/coarse harp screws)
They're killing the sustain of a few notes when tightened and are too short/worn to be shimmed with card as the service manual suggests.
Thanks !

I'm finally getting round to restoring my Wurli and wondering what models/series of electrolytic capacitors would be best for the pre & power amps? It's a bit of a minefield with things like ESR so any help would be greatly appreciated. (I usually end up using Panasonic, Vishay or Nichicons for synths & outboard equipment)

I've already bought replacement transistors and I'm working off this Vintage Vibe schematic.

Below is a list of parts I've put together that may need replacing in future. The caps are noticeably worn so I'll start with those and the preamp transistors to reduce the noise. If there's anything else worth looking at whilst I'm in there, please let me know.
Thanks !


Electrolytic Caps:
5, 6, 8, 26 - 4.7uF
7, 10 - 22uF
12 - 100uF
23 - 1uF
27 - 47uF
28, 29 - 2200uF

Film Caps:
30, 31, 34 - 0.33uF (Panasonic ECW-F2334JAQ)

Metal Film Resistors:
1 - 22k
2 - 1M
3 - 470k
4 - 150k
5 - 33k
6 - 1.8k
7 - 270
8 - 820
9 - 6.8k
10 - 56k

Transistors (spec sheet here)
TR1, TR2, TR15 - 2N5089
TR3, TR4 - 2N5088
TR7, TR8 - 2N5087
TR12 -  MPSA56
TR9, TR10, TR14, TR16 - MPSA06
TR16 -  KSP13BU (later serial # pianos - post #102905)
TR11/TR13 - TIP35C & TIP36C (power output transistors)

I'm restoring my Rhodes and need to remove the hammer cam felts to do the 'miracle mod'.
I was going to leave them on and just apply the bumps but a few are quite worn!

I have available - lighter fluid and methylated spirit. I have a small amount of isopropyl alcohol, but not sure where I can buy more locally.

Supposedly denatured alcohol is the best thing to use, is that the same as methylated spirit in the UK?
Thanks!

I have a Rhodes 88 Mk1 ~1975 that I'd like to get professionally serviced. It's fully working but could use new action pieces - felts, hammer tips, grommets, etc and a nice set up.

A Google search brings up a few companies in the UK who service & restore Rhodes and I'm keen to know if anyone on this forum has experience with any of these companies or recommendations?
I'm based near Oxford, so South England would be preferable.

I'm also considering the 'Miracle Mod' to get a nice quick action.

Many thanks!