CX-600 Thread. My bucket of mistakes and learning experiences.

That white glue is a bitch to completely remove without scuffing the PCB.

Well, I had reasonable success, got almost all of it off with only a few scratches. Except for where it got under some jumpers, resistors etc. I'll have to remove them to get the rest, but since I was going to do that anyway in this area I left that for later. Acetone helped a lot.

Cheers,
James

DSC02568.jpg
 
What is your plan for the RCA jacks ? OEM or after market ?

I haven't gotten as far as having a plan for them other than cleaning with a 10m socket, a rag and deoxit. At least on this unit they are all gold plated. But several of them have solder connections that look questionable. I'm completely open to suggestions as to replacements.

Cheers,
James
 
What are you using for that memory back up cap. C227-- 4.7 millifarad / 5.5volt ?

Heh heh. You aren't "Avionic". You are "Radar Laser Clairvoyant". When I first saw that cap I thought "that's a damn big cap for 4.7µF. Huh?". Only later when looking through the parts list did I realize that it is a 4700µF cap. m, not µ! And started looking yesterday. The diameter is a problem. Looks like 10mm and the smallest that I can find (in 6.3v, nothing smaller can I find) is 12mm, most are 12.5mm. It will be tight. And I took a snapshot and was about to post a question as to what it's purpose and special characteristics are. Hence "Clairvoyant".

These are the 2 best looking options that I've found so far...

http://www.mouser.de/ProductDetail/Panasonic/EEU-FM0J472L/?qs=MtOUKumLmna17tjgk%2beJAg==
http://www.mouser.de/ProductDetail/...YB6R3ELL472MK25S/?qs=IYueExuAvkrUWaGgtWDNUA==

I'm open to suggestions, and opinions as to which of the above would/might be best.

Cheers,
James
DSC02553.jpg
 
Farnell has the switches also and today I went ahead and ordered 3 of the SPUN191400 and 2 of the SPUN 194700. That latter switch is shown by Mouser and in the pdf as latching but Farnell shows it as monentary. So with the hope that Mouser and Alps are more correct than Farnell I bought 2. If that turns out wrong than I'll have 2 pretty little things that I can put in a picture frame or something. But the monetary risk isn't very high so I can live with that.

Cheers,
James
 
Came down with the flu so progress is a bit slow right now. I have the entire board re-flowed now. Pulled Q407 and my little checker gave values of B=148 and Uf=606mV. I have no idea if those are good values. Digi-Key shows a Fairchild KSB1015YTU as a direct replacement for that 2SD1913 and Mouser has that one also.

http://www.mouser.de/ProductDetail/Fairchild-Semiconductor/KSB1015YTU/?qs=ljbEvF4DwOP0LgPE7HhE1A==

I haven't pulled anything else yet. The only caps that I'll have to order for the power supply area are the big filters plus C415 (22µF/25v) and C417 (the one that's bulging)(470µF/16v). For the rest I have UCC KYB and Panasonic FC for them all and in at least one step higher voltage class than original. I haven't gotten as far as checking for what I need for the rest of the caps on the board yet.

There are quite a few elcos in the signal path. I've read in some of Leestereo's threads where he replaced signal path polar elcos with bi-polar elcos. Is that a good practice? I have some Nichicon Muse ES on hand and would order more if there is a benefit to be gained. Otherwise I'll use KZ or FG in the signal path.

I have a bunch of 1N4148 and 1N4007 diodes on hand. Can they be used as subs for the original 1SS133 and 1SR35-100 diodes? Looking at the datasheets I had the thought that they would work but am not sure.
The new switches arrived yesterday. The news is mostly good. The 4-pole SPUN194700 is definitely a drop in replacement. :banana: So the Source Direct and Phono MM/MC switches can be replaced with no pain.

But the SPUN191400 is different in one aspect. The original has a base riser about 7mm high that's missing on the new switches. So if used as-is they would sit too low on the pcb and not line up with the holes. But I plan on cutting some pvc stand-off blocks, drilling them to fit the leads and lengthening the leads with 1mm wire. Don't see why that shouldn't work. In any case it can be used for the power switch as-is. The little pcb just solders to the lugs and hangs in the air and there's clearance. So at the very worst my power switch problem is solved and I have a little modding to do or I can still elect to clean the 2 old switches if that doesn't work.

Cheers,
James

edit: the switch riser on the above works out to 6mm


DSC02574.jpg DSC02575.jpg
 
Last edited:
Give one a shot. If the pre loses its mind before you do. I guess it didn't work..:biggrin:

Sounds like a plan. I don't know how much mind I have left so the amp should win. Looking deeper I now understand that apparently this spot uses a "supercap". And looking at what's available I'll have fun fitting one of them. So for starters I'll go with the above idea.

Cheers,
James
 
OK. Thanks for the answers guys. I'll consider it. I'll check which ones are in the signal path and then decide.

Today I spent some time looking over the schematic and board. There are 16 resistors in the signal path. I can't really afford to replace all of the carbon film resistors in the entire pre but certainly can afford to replace the ones in the signal path with metal film. So I'm making a list, Vishay CMF 1%. And I'll add all of the resistors in the power supply to the list on the grounds that they've probably been getting hotter than ones in other areas.

4 of those resistors are fusible, and I would like to replace all of the fusible carbons, there are only 14 total. But there is a problem with that. I would need (for the fusible resistors):
1x 3.3 ohm
2x 3.9 ohm
1x 10 ohm
2x 22 ohm
4x 33 ohm
4x 100 ohm
And the only ones that I can find at Mouser in 1/4w are 10, 33 and 100, all in 5% (Yageo). I'm not seeing 3.3, 3.9 and 22 ohm in 1/4w. So I'll have to look some more.

There are 23 elco caps in the signal path. I was looking over the schematic trying to read the voltages along the signal path and saw a high of 14.1v (in the phono section). If that is correct then I would think that 25v caps would be enough. So I would have enough Nichicon ES PB caps on hand (6x 10µF & 8x 47µF) to replace all except 4 caps. Those 4 I'll have to order (2x 330µF & 2x 100µF). The larger size of the BP caps will be a challenge in several cases but I think that if I get creative it should work.

Tomorrow I'll go through the rest of the elcos and make decisions as to what types to use and sort through what I have on hand.
So I'm slowly getting to the point where I can put together an order list. On the weekend maybe.

Cheers,
James
 
Last edited:
OK, so I just made a large order with Mouser.
The relay, all of the remaining caps that I need with a few variants (more on that later), all of the zener diodes that I need, with extras and variants, 100 of those SBYV27-100 diodes (extras for bench stock), 10x SB1H100-E3/54 diodes, all of the fusible resistors that I could find (10, 33 and 100 ohm), and a slew of other metal film resistors. I can't really afford to replace all of the carbon film resistors at this time so I prioritized. All of the signal path, and everything in the "0db amp", "source direct amp", "flat amp" and power supply. I ordered resistors for these sections, as well as some to finish a cd player project.

For transistors: KSA940TU, KSB1015YTU, KSC2073TU 2 of each. KSA1015YTA and KSC1815YTA 25 of each. (KSA992 and KSC1845 I already have). So I have enough to replace a good part of the transistors on the board if so decided/needed.

And some op-amps. LME49710HA/NOPB and LME49720HA/NOPB for some cd players, and LME49860MA/NOPB for this unit in case I decide to replace the 5532DD JRC op-amp in the "flat amp" section. I would liked to have tried out a pair of the LME49710HA/NOPB on an adaptor for that section but they max out at 17v supply and I see 20.9 volts on the schematic. I have soic8 to dip8 adaptors on the way. I really love that LME497x0 series.

Pictures and details tomorrow but I have a good portion of the board recapped now.

In each and every case I ordered more than the minimum needed, I figure that everything that I end up not needing for this pre-amp will be useful for my bench stock and will end up getting used on other projects.

Cheers,
James
 
The only thing worse than waiting for parts to be delivered is... no, there is nothing worse. But as I'm waiting I started de-oxing the pots and got the switches ready. After re-measuring the old switches I got exactly 6mm for the riser. And got lucky and found a piece of 6mm pvc scrap at work. Cut 2 pieces, drilled and then filed/cut reliefs for the jumpers on the pcb under the switches.

I measured 1mm on the switch legs and drilled 1.5mm holes in the blocks. The wire that I used for the leg extensions is 0.8mm dia. Pre-tinned the wire and legs before soldering. And as I wanted they were a very tight fit getting the switches onto the blocks with the leg extensions. Had to really press them together. I'm hoping that this will hold the wires in place on the legs when I solder the switches to the board and not allow them to separate. Did a provisional test fit on the pcb and everything lines up pretty well.

After that I mounted the power switch to it's pcb and installed it's mounting plate after removing the little plastic box frame on the front of the switch. The mounting plate fit perfectly. Parts order from Mouser is supposed to be here on Friday.

DSC02601.jpg DSC02604.jpg DSC02605.jpg DSC02606.jpg DSC02609.jpg DSC02611.jpg

Cheers,
James
 
Thank you! Btw, that's an interesting looking bike in your avatar. What are you riding?

Cheers,
James
 
Back
Top Bottom