C33 Update Project 2013
- Thread starter Gregory
- Start date
Gregory
Soundco Kid
I see you've posted a recap fail in my C33 project thread. Sorry to hear about the trouble. It's important to check and double-check your work, especially to inspect solder joints. Some of the guys use magnifying glasses or eye-pieces... i use a Canon digital camera in macro mode.
Look for a PM later today, in reply to your PM.
-Gregory
Gregory
Soundco Kid
Been about half a year since the Update project was wrapped-up. The C33 has seen a LOT of use since then, sometimes running from early/mid afternoon till after our night time Blu-Ray move. It was working flawlessly and probably could have gone longer in stock condition.
One minor issue after recap
One issue DID show-up after the recap. The REC EXT PROCESSOR circuit cannot be used. If anything is connected there, one channel either whines terribly of does a `thump, thump, thump.´ I reckon one of the Ext Proc jacks is bent or somehow got damaged.
Is there any known history of Ext Proc jack problems? This circuit is required.. because I'd like to hook a Graphic EQ to there, and simply press REC Monitor to apply/remove EQ.
-Gregory
One minor issue after recap
One issue DID show-up after the recap. The REC EXT PROCESSOR circuit cannot be used. If anything is connected there, one channel either whines terribly of does a `thump, thump, thump.´ I reckon one of the Ext Proc jacks is bent or somehow got damaged.
Is there any known history of Ext Proc jack problems? This circuit is required.. because I'd like to hook a Graphic EQ to there, and simply press REC Monitor to apply/remove EQ.
-Gregory
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On the picture of #045809 board taken by Gregory, big cap 10uf 200v placed in opposite way +/- comparing to schematic. Is it right or wrong?
Added my pictures of this board to compare how cap is placed. Also bi-polar cap 10uf 25v was shorted during replacement, causing problem to power on.
Added my pictures of this board to compare how cap is placed. Also bi-polar cap 10uf 25v was shorted during replacement, causing problem to power on.
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kevzep
Its all about the Music
are you in the USA 120V? or are you in a 220-240V country? that looks like over-voltage to that circuit..........
Gregory
Soundco Kid
Suppose I'm not feeling all that sharp today. C1302 used in the Auto-On board 045809 is across the AC input power relay with a 110 VDC solenoid. The cap seen in the photo is the original cap, and I didn't replace anything on that PCB. Wasn't broke so didn't touch it.
-Gregory
kevzep
Its all about the Music
Suppose I'm not feeling all that sharp today. C1302 used in the Auto-On board 045809 is across the AC input power relay with a 110 VDC solenoid. The cap seen in the photo is the original cap, and I didn't replace anything on that PCB. Wasn't broke so didn't touch it.
-Gregory
yes that's right, and this is often what is missed in a 120 to 230V conversion. That circuit is connected directly to the incoming mains in 120V, but in 230V it is connected to one on the windings on the primary side of the power transformer.
I am thinking that this unit has had an incorrect voltage conversion done to it.......but I dont know the members location is not on his information...
jcameron5171
New Member
I love the pictures but I would really love before and after video/audio clips.
kevzep
Its all about the Music
Yes if the cap was the wrong way round or a polarized when it shouldn't the yes you could have this problem.....
Changed polarity. It works. Thanks.
Another puzzle. On original main board caps C526, C527, C528, C530 were placed with different polarities comparing to schematic. Equalizer board has also puzzles. Caps C721, C722 also show different polarities according to schematic. What is your opinion? Does it need to be replaced?
Another puzzle. On original main board caps C526, C527, C528, C530 were placed with different polarities comparing to schematic. Equalizer board has also puzzles. Caps C721, C722 also show different polarities according to schematic. What is your opinion? Does it need to be replaced?
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kevzep
Its all about the Music
What I do when re-capping a working unit, not matter what it is, I take photos, and follow the orientation which the unit already has and ignore the schematics.
Often mistakes and updates, service bulletins and such make those diagrams not that reliable to do such a job with.
If the unit is working, then put them in the way they came out.
Do them one at a time.
After one board is complete, turn the unit on and make sure it is working so that if you do have a fault then you know where it is located.....
SeattleHiFi
Active Member
Gregory, would you say the sound quality of your C33 has improved after your recap? And if it has how so?
Gregory
Soundco Kid
I think the sound is cleaner, maybe a better S/N but have no test data to show any change. There are still a few caps on the EQ board that are stock, like v-rail bypass. The front panel wasn't removed.
The C33 was running perfectly, and frankly I didn't believe it needed a recap yet.. and probably met specs. There's always a risk of DAMAGE when you `dig in´ to a unit, and that damage could range from minor (lifting a trace) to major! (like a totally blown circuit.)
It was a good exercise. Electrolytics do age and dry out, etc. plus newer mfg caps today have better specs and are more uniform (again no backup data).
It got broke
Something is broken in the EXT REC PROC circuit, and than means "back on the bench." Probably is the shorting jacks on rear panel.
I think anyone with Mc gear older than 20 or 25 yrs needs to pull them out (disconnect) occasionally, open the covers and inspect for contamination, oxidation, etc. and give them a couple ssst, ssst of switch and pot juice.
Also be CAREFUL not to scratch the case or panel like a Bozo. <--sometimes I put that in posts. Lol
-Gregory
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Gregory
Soundco Kid
John.. you comment above was skimmed over when originally posted. Now I'm taking note of it.
-Gregory
I would like to make a comment that applies to ME and my C34V's. It may apply to Gregory, it may not. These vintage units would need a recap eventually. I am a retired electrical engineer. I am the kind of person that enjoys looking at the inside of a preamp as much as the outside, gets satisfaction seeing 80+ high quality Nichicon caps sitting perfectly vertically positioned on the circuit boards, with perfect solder cones beneath them, I assure you, when I turn it on, the unit will have dropped 0.5% THD whether it did or not. It was a labor of love and the satisfaction of working on my units was worth it. I should point out I am a perfectionist in some regards but a complete scatter brain compared to Gregory in others. He leaves me in the dust. :yes: