3below

Big One, excellent cab, lots of bottom end. From experience It has a healthy appetite for Watts, check out the sensitivity of Eminence 3015LF. I moved mine on for a BF Dubster, no lack of bottom end

I have one fretted, plus a fretless. As above, ask away.

Why do I have an uncomfortable feeling about the latter and headstock breakage? What problem is it a solution to?

Yes and yes, although the PCB makes the construction simpler / neater / easier than point to point wiring when you are manufacturing thousands (or more) of the preamp. Stating the obvious, when you re-build it you will solder the new pot onto the PCB.

The little black thing with a stripe is an electrolytic capacitor. The pot (in the model circuit) is 20K. The best bet is to de-solder the pot and remove it from the little board. You will have to do this anyway to replace it, de-solder braid and or a solder sucker are useful. Get a multimeter (a cheapie 10-12 Euro one will do), and measure the resistance between to two outside terminals (legs).

Looking at your images confirms it is not the above circuit, the treble capacitor on your board is C6, on the schematic it is C3. Must look more closely at the evidence in future Having said that there is no reason why the RC combination in that circuit could not have been used in other preamps.

Those appear to be 20K, 19.8K + 0.2K.

A quick search does not find any schematics for a BII pre-amp. However, this circa 2008 looks promising https://www.talkbass.com/threads/fyi-ibanez-sr480-preamp-schematic-jpg-pdf.455174/. The pot values are shown as 50K Ohms. I would imagine that the amp designs would not have changed much in that era, you could look which IC is fitted - TL062? On the treble pot board, can you see what value the capacitor has on the side, and what colour code and hence resistance the resistor is. This will help confirm that it is the schematic above. The best answer would be to desolder the pot and then measure the resistance across the two outer legs.

Are you replacing an existing pot? It could be logarithmic or linear either side of the detent. Are there any legible identity codes on the pot? If not you have four possible ways forward. 1. Ask the manufacturer what pot is fitted, 2.Search the internet for a schematic or clone schematic which might show the pot type, 3. Make some basic measurements, using a multi-meter and determine if the pot is log or lin, 4. Buy a log and a lin centre detent pot. Try them both and see which you like. What preamp is it? the BC collective wisdom may know the answer to your question.

Hence the change plus the removal of "by Leo Fender" on the decal. I have both versions, I prefer the early style one but don't notice (avoid noticing) the shape of the later one when playing it.

Message @Andyjr1515, the master of such repairs among many others.

Take it to a good, reputable luthier. I have two I can suggest but they are both a long way from Norfolk so of little use to you.

Totally agree, I was just thinking about the angle the Allen key emerges at from the slot. Some judgement by the end user is required. Imo, the slot under the Chowny truss rod cover could do with being a few mm wider to make regular Allen key use easy.

One of 4mm, 5mm or 6mm. Can't remember exactly which one since I have not adjusted my brace of them in ages. I do remember you might be better to use one of these, the truss rod slot is relatively narrow. Ebay has some Draper sets at knockdown prices. Your local hardware shop might be equally competitive.

Following on from @Dad3353, sometimes you will encounter a bass (or guitar) that you just can not get sorted. Symptoms of a deeper problem where, stating the obvious, the luthier setup is the way forward.

Great advice from @itu and @Dad3353. One further aspect to consider is whether you loosen the strings before making adjustments. I always adjusted truss rods with the strings in tune, never had a problem with 20? 30? basses. I then encountered my G&L L1505, got stuck in and terminally cracked the fretboard off the neck. Fixed by Jon Shuker (new board, better than new). The advice I was advised to slacken the strings,adjust and bring back into tune. @itu suggests wait an hour which is good advice. Most basses in my experience respond pretty quickly, the hour is a good figure. Some do not, my Warwick Corvette (baseball bat neck) takes several hours to respond. There are many good videos on YouTube on action and truss rod adjustment. Remember also that there are no absolute measurements /settings. Strings, condition of frets, your playing technique all play a part. I have a heavy right hand technique, 2.7mm to 3mm at the 12th fret is the result.

From what I read, Fender neck screws are 8 x 1 3/4. 55mm is 2.1" so 8 x 2" screws might be suitable. These might be worth a try https://www.ebay.co.uk/itm/361547596279?itmmeta=01HZ363NKT4JDF6HZSVJBNAFEW&hash=item542dea81f7:g:jsYAAOSwNptbyb-l&itmprp=enc%3AAQAJAAAA4GIGaTJNJoW9nyTYfGFLL%2BNnBZsQ1zWPezYebmeURcnd%2FdMtR95V7Ox0YqhkGTLIjNv%2Bkmg%2BK23vBi89cXNgmP2BZsyctxwNt5HxSI5QAQGvIcqbMQoH0sC7KuVPxO%2BPq0COH4697NhW8ljq9HiVvaNTCuBt2d8rAUvNhf1IXwsS09876RRf169i6RvDKZoIX0e6pqF0m66QnsoGG9tk9Y462fEPX2L7Wn7A3zQb6KRtZ%2FKai0XkMhlioHE35FM7xCiO9FdIz%2BqYsBgFe1pm4hvtRiOw4HouanyH%2B0JF2SSA|tkp%3ABk9SR4Tajub4Yw or https://www.ebay.co.uk/itm/232283099384?itmmeta=01HZ363NKTP82S6379BXSK26QB&hash=item361526d0f8:g:aWwAAOSwsW9Yzc3~&itmprp=enc%3AAQAJAAAA4M25%2B35hz0DA2jJv%2F7u%2Bx4%2Bgx1dzyNKRwYNxn%2FNwsDq4Qvwhf7HLAmS9YEllYud7EsRiMdGmbtKRny5UN7R1%2FQfPIWp0Tw3ZtyByMcIBa%2B74n08a%2F8nORviAMsVQgLTeFDI7kbkHu6C%2F9qJGCguVyYFH1cjiQoI0rngzBPonZN7XBVtV6hVZkuVXOrrAnRYY74%2BNl9INfLVySMgnpKqYEtqUnGfsXGB9jFdb3r4SmBBLtvi4I2YPu90RXriFSMJdOVYKV1ud0W5jZsjSQ%2FKtxoZaroUXCg2vkknnwA0S2mdj|tkp%3ABFBMhNqO5vhj I had to buy a few types until I found something suitable when I did the same mod on my Chowny SWB-1. The screw head required filing to make the diameter small enough to fit a straplock. Check the depth measurements carefully (again, since you have done so), I had to file a small amount off the screw tip, emerging through the fretboard is best avoided.

They just look so cool, makes me think about building a lightweight clone using a Rumble head. Then again the time is probably better spent playing bass.

My third transaction with Lee. The weather was not as good as last time (11/12 yrs ago on a cab swap, you may get it back one day when I stop playing lol) but Lee was just as great to deal as the last time. Great organisation and communication, you could not ask for a better BC chap. The kit I bought is also rather good. Top man!

^ Great practical advice.

Up to a certain size venue it is still possible to do it 'old school' in a sane manner. I have done the 'too loud' band thing which required ear protection,glad to leave that one behind. My first line band plays venues of 100 - 200 currently. No mixer, pa vocals only, horns not miced, guitarist with 40W combo. Plenty loud enough for our audience and 'show'. The key to this has been discipline, get a good mix at a sensible volume (lighter drumsticks I am told by the drummer) and do not change it. So far so good as we are all old hands at this. If we get to bigger venues needing full pa support this method will hopefully still work, the pa being louder than the band. I would miss the physical feel of my bass going full silent stage however I fully understand the reasons why many do.

AI, that would be Absent Intelligence.... (apologies folks that was too easy a target to refuse).