| Author | Message | ||
| Chuck Bryden (cbryden) Username: cbryden Registered: 12-2006 |
Here's a scenario.. been a busy year for me for gigs. Love my Zen Drive into my 410 65 hd with phase inverter. Played a gig thurs night - the amp was just awesome. Put everything away (working 100 pct), left the amp in the car thurs night, worked friday, was involved in a near accident where I had to panic stop, may have jostled the amp around some. (but still, doesn'ts eem a whole lot) Come friday night, DOA. - When I plug in and turn on the power, no tubes light up, no pilot light. - Convience AC receptacle still has power - Changed the fuse, the old one didn't look burnt. No luck there. - Had to play the gig with my backup, a mesa boogie subway blues, with my 4x10 as an extension cabinet. Great little amp but it just wasn't the same. What are the easy stupid things i should check for before bringing my 80 pound baby to a local tech here in town (who has a good rep from all my friends not sure about MM though). At this point I sort of assume a compent became loose or dislodged somewhere from the amp being moved. Where should I or a tech look? Thanks for any help, Chuck | ||
| Chuck Bryden (cbryden) Username: cbryden Registered: 12-2006 |
update - i pulled the chassis and found the culprit. There is a little see through doodad (im not an electronics guy) attached the the right-hand side lug of the fuse socket. It contains what appears to be a bimetal strip. The wire going to it has broken off, breaking also the lead into this doodad. The other lead from it goes to the group switch. What is this thing? Is it some sort of secondary fuse? I intend to replace this. Anybody know what to use? | ||
| Chuck Bryden (cbryden) Username: cbryden Registered: 12-2006 |
to make up for my lack of electronics know, I am 99% sure the 'doodad' mentioned was in the schematic below, lower right hand corner, trace up from where the 120 comes in, go past the 5 amp fuse, the next thing up. it's called a "CB-I 58609CIG SYLVANIA" That's the little doodad i am talking about that comes off the right hand (from the back of the chasssis) and goes over to the ground switch. Anybody knows what this is? Thanks for the help. http://www.pacair.com/mmamps/schematics/ Clapton_HD130.pdf | ||
| Chuck Bryden (cbryden) Username: cbryden Registered: 12-2006 |
Here's the best pic i could get of this "doodad" http://viewmorepics.myspace.com/index.cf m?fuseaction=viewImage&friendID=20827754 5&albumID=131635&imageID=15575746 | ||
| Mel Hadden (merkle) Username: merkle Registered: 01-2007 |
That :doodad" would be a neon lamp. | ||
| Mike Kaus (mm210) Username: mm210 Registered: 05-2006 |
I actually never understood why they put that in there, unless it was some kind of extra circuit breaker. I usually find them broken and just go around them. I guess it could be for filtering but I would think it would cause noise actually. Their component name says CB-1 like it's supposed to be a circuit breaker. Like I said, I usually find them broken and just dispose of them. | ||
| Chuck Bryden (cbryden) Username: cbryden Registered: 12-2006 |
So you think i'm not really taking my life in my hands as long as I never cram a paperclip in my fuse holder or something? If I wanted to replace it, I could probably use any 120v crappy light from Radio shack? | ||
| Mike Kaus (mm210) Username: mm210 Registered: 05-2006 |
PROBABLY, but I couldn't find any info on that particular lamp so personally, I'd take the wire from the fuse holder and go directly to the switch and be done with it. Every fender amp from start 'til now got by without a lamp inside. Who know, maybe it was Leo's idea to keep the little tiny electron from getting lost in the dark! | ||
| Chuck Bryden (cbryden) Username: cbryden Registered: 12-2006 |
bypassed the bulb. Amp works and doesn't melt or shock me! Thanks for the help. I'll be glad to have the MM roar back this weekend. As far as amp safety, and some vague gibberish i've heard about the guitar being at the negative tip of the circuit or something, any tips for general safety? I was thinking of getting a ground fault power strip, so if there is ever a short while i am playing, or i sit in a puddle for the big solo, i hopefully don't get shocked. Any thoughts from anyone? | ||
| Mel Hadden (merkle) Username: merkle Registered: 01-2007 |
Make sure you have a three prong gounding plug and power cord wired correctly. | ||
| Mike Kaus (mm210) Username: mm210 Registered: 05-2006 |
I used to use a GFCI for just that purpose but lately(I'm getting old) I just plug in and go. Three wire is the thing and don't stand in the puddle! | ||
| Chuck Bryden (cbryden) Username: cbryden Registered: 12-2006 |
When I bought the amp, it the power chord looks as though the third tip broke off. Did these come wired from the factory for three prongs? If so I will just get one of those clamp on ones from the hardware store, cut off the existing power plug, strip the end of the wires and put it on. Seems like a simple job? | ||
| Mike Kaus (mm210) Username: mm210 Registered: 05-2006 |
Yes they were all three wire then. Wack the end off, black wire goes to the brass screw on the plug, white goes to silver, green to green or ground. Make SURE you wrap the ends of the wire around the screw to form a little hook to help as a strain relief. I PERSONALLY usually make the hook first and then solder the hook in that shape. Gives a little more strength. | ||
| Chuck Bryden (cbryden) Username: cbryden Registered: 12-2006 |
thanks. I've got one gig tonight and then off for the weekend. So i'll do that this weekend. I also picked up a GFI power strip thing. Between the two (and not jumping into fishtanks for the big solo) I should be as safe as reasonably possible. I don't know why I haven't thought of it before, I guess staring into the chassis fixing that wire made me thing of all that juice in there. | ||
| Mel Hadden (merkle) Username: merkle Registered: 01-2007 |
With the ground broken off your plug, the GFCI won't be effective at all. The GFCI senses current flow through the ground connection. I'd advise replacing the plug end before playing. When I was in the Air Force circa 1970 stationed in Fairfield, CA., we had a guitar player electrocuted (fried, died) onstage while playing and singing a song at the NCO club. No lie. I personally didn't see it but a bud did. Upon investigation it was found that most of the equipment the band was using wasn't grounded and the guitar player's amp was wired backwards, hot was chassis level. When he approached the mic to sing a blue flame appeared between his face and the mic killing him fairly quick! After that incident, all bands appearing on the base with anything powered by the juice first made a stop at the electric shop to have their gear checked for proper grounding. If it wasn't right it was fixed no charge. It is a big deal !! | ||
| Mike Kaus (mm210) Username: mm210 Registered: 05-2006 |
Mel's right about that. If the pins gone, you HAVE no protection. In a pinch, you CAN use a wire clipped to the chassis and to ground but make sure the clamp is tight and secure. Those little grippers on the clamps don't provide much path if there is a current surge. It's better than nothing. | ||
| Walter Jowers (sonofswamp) Username: sonofswamp Registered: 08-2006 |
Actually, the ground pin on a 3-prong plug has nothing to do with GFCI function. A GFCI just reads an imbalance between the hot and neutral. More info here: http://home.howstuffworks.com/question11 7.htm | ||
| Chuck Bryden (cbryden) Username: cbryden Registered: 12-2006 |
I was kind of thinking the lack of third prong on my plug wouldn't negate the GFI either, after all I have one of these in my bathroom, and my shaver, electric tooth brush, etc, are all two prongs. However, I do agree it is a big deal and I got a new 3 prong plug to clamp on the end, which will be done before I run the amp again. Should a short happen, I'd rather the extra current, even if it exists for only microseconds (before GFI cut), to flow through that third tip and not through me! Thanks to everyone for all the help - not only do I have the beast running, but i'll have a replaced 3 pin power plug and be much safer that I was previously, should something ever go wrong. This is a great message board. An electronics novice like myself would have never gotten into a MM if it weren't for this resource! Chuck | ||
| Mel Hadden (merkle) Username: merkle Registered: 01-2007 |
How would a GFCI know what an imbalance of current is? Is there a setting on a GFCI device that you can tell it "oh, this device uses 5 amps normally" The last paragraph from the 'howstuffworks' tells you how the device works. "" some of it is flowing through you to ground. As soon as the GFCI senses that, it trips the circuit and cuts off the electricity"" The GFCI senses current flow between 'hot' or 'neutral' and ground not hot and neutral. Hot and neutral are two different current carrying points. Ground should not carry any current whatsoever so the GFCI device senses that current and trips incoming power. If this is wrong then I've been getting electrocuted every day for thirty plus years! A lot of these websites are written by people who have no idea what they are writing and can put people at risk from their misguided information. "Howstuffworks" seems like one of those sites. | ||
| Alex H. (alex_h) Username: alex_h Registered: 07-2007 |
Here's two articles from more reputable sources: http://www.iee.org/Publish/WireRegs/Wiri ngMatters/Documents/Issue19/2006_19_summ er_wiring_matters_understanding_rcds.pdf http://www.cpsc.gov/cpscpub/pubs/99.html | ||
| Chuck Bryden (cbryden) Username: cbryden Registered: 12-2006 |
3 prong plug installed successfully. Thanks for all the help getting my amp running right and safer than before! | ||
| Mel Hadden (merkle) Username: merkle Registered: 01-2007 |
Shave Heads!! | ||
| Doug Spears (douglasspears) Username: douglasspears Registered: 10-2008 |
haha, I was kinda hoping Chuck would not have posted for a few days following the 2 prong gig. Coulda led to some interesting speculation, haha?!? Good to have you back Chuck  |