Help! I need schematics for a crate flexwave 120h

[Trae617]

I bought a crate flexwave 120 with a 4x12 half stack off craigslist for $250. I tested it out before I bought it and it sounded good, and the guy I bought it from was a pretty well known re-seller of used equipment so I wasn't too concerned. I had it for about 3 days and the effects processor started kicking on randomly and now the overdrive channel won't work at all. When i push in on the knobs it will pop and kick on but if I let go it kicks back off again, and the volume control is awful. The high gain channel still works, but it's quiet. The clean channel works fine but the flanger will turn on by itself at random and at full blast. Drives me nuts.

I'm really not wanting to buy another amp because I love the way it sounds (when it works) so i'd really like to fix it. All I really want is the clean, OD, and high gain channel. If the onboard effects never work that'd be fine with me i don't really care for them anyways. Could someone give me some guidance or advice? I'm kind of electronically retarded so schematics would probably be over my head but I'm going to try everything i can before i give up on this amp.

[DrGonz78]

Well posting a schematic may prove to be over your head, but to some here it will help them "help" you better. Plus you can read it a bit to understand the basics of the circuit. How handy are you with a soldering iron? Put the amp on the overdrive channel and give the amp a nice hit with your fist.  :trouble Now we are wanting to hear if the signals returns or responds suggesting a loose connection. Do the same on the High Gain channel too. A lot of times cold/cracked solder joints or dirty jacks can cause all sorts of havoc in amps shunting the signal. So, we need to do this basic test to see if it responds to getting whacked. :duh

Look on page one of the schematic that I have attached, quadrants (B,3) bottom left. It says something about the DSP PC Board (pins soldered to preamp). Notice that it says switch lines... DSP pin14= clean, DSP pin16= solo/od. I would be making sure that all the solder joint on all the pins connected there are good.

Basically, that is a simple way to start thinking about troubleshooting the amp. Give us some feedback as to what you might find and describe all symptoms with as much detail as you can. Good Luck.

[J M Fahey]

FWIW that crazy schematic shows the speaker with a wire ***shorting*** it  :duh :grr
Just check TP13   :loco

[Roly]

Title block;

"Drawn: REM 09/06/05
Checked: {blank} "

:lmao:

[Trae617]

Thanks for the advice and schematics! yeah, this is so far over my head it's not even funny. I've got a buddy that was a radioman for the marines and he's an electrician now so maybe he can help me out with this haha.

I really appreciate it! I'll post an audio file if i can get it working again!

[paran0ic]

Hey! Thanks for sharing the schematics! I was looking for it! Im tried to repair one its sound like some buzz, maybe some lost ground, tomorrow will be checked! :dbtu:

[phatt]

Just reading the symptoms,,I'd guess switching troubles.
Maybe jiggle J21 and J32.
In my experience a lot of modern stuff use those pathetic ribbon cons and I've experienced quite a few that go intermittent. Also If you can find those test points around the switching circuit (all the stuff hanging off J21) make sure they are reading to spec.

Also don't forget that ever painful efx loop/send return/insert as they often give trouble. :trouble
With no plug inserted, pins 1&2 of J32 should read zero Ohms.

likely those sockets are encased plastic types and although the idea is good they are weak and go brittle over time. I've had some fall apart just inserting a plug and also found some with the guts all mangled. They are not very robust and I avoid using them if possible.

Start with cheap problems before you assume expensive stuff has broken, winky.
Phil.

[MMurphy120]

I know this is a old posting but I though I would post to it anyway just in case someone searches to it with the same issue. I also bought a FW120H that had the same symptoms with the effects turning off and on randomly, volume jumping,  and the 3rd channel would stop working as well. I noticed that the leads from all the pots are crimped at the pot its self so that could potentially create an intermittent connection and intermittent issues described in this forum. I took a 27 watt soldering iron and lightly soldered both sides of all 3 crimp locations on each pot itself and not at the board and it solved all my problems but one which appears to be a bad IC. I found the connection issue by powering up the amp with the board out where I could flex it looking for cold solder joints and cracked PC strips. I noticed if I held the board firmly and flexed the pots the intermittent problems would disappear. Now if you are not experienced with working on amps with power applied, do not try this because it is a serious shock hazard. Let me repeat, do not do it if you are not experienced with that form of troubleshooting with power applied. You can do all the soldering with power not applied and just look for positive results after its reassembled. Either way good luck because it is a good sounding amp for the price. Got mine for $120

[teemuk]

FWIW that crazy schematic shows the speaker with a wire ***shorting*** it

i think the JWOPT = "Jumper Wire, Optional" -remark might have something to do with that. They use the same boards for many different amps, perhaps one is a head and benefits from short circuiting terminals that, without an internal speaker connected, would provide no continuity to following interconnects like headphone or external speaker jacks.

Or maybe they just build it like it is and there's a giant batch of Crate amplifiers that self-desctruct when you plug them in. Come to think of, I never heard of such thing. 

[J M Fahey]

FWIW that crazy schematic shows the speaker with a wire ***shorting*** it

i think the JWOPT = "Jumper Wire, Optional" -remark might have something to do with that. They use the same boards for many different amps, perhaps one is a head and benefits from short circuiting terminals that, without an internal speaker connected, would provide no continuity to following interconnects like headphone or external speaker jacks.

Or maybe they just build it like it is and there's a giant batch of Crate amplifiers that self-desctruct when you plug them in. Come to think of, I never heard of such thing. 

1)

Modify message
« Last Edit: Today at 07:36:22 AM by teemuk [/b]»

Please explain WHY do you edit MY posts without asking? :loco

2)
Labels in that schematic are either self explanatory, such as:
"pwramp" which uses 3 letters to mean "power"and 3 to mean "amplifier", "+40V" which is clear enough, "9 pin hdr" (which uses the full word "pin"and 3 letters to mean "header") and so on,
*or*
when meaning is not clear, there is an explanation note, such as:
"connects to chassis ground" , "to jack board external speaker jack" , "on 120W versions" , and so on.

NOWHERE in that page is an explanation or clear description for the acronym "jwopt2".
Also NOWHERE it mentions that "said connection is used on certain models and not in others", the original poster trying to repair his amp might even see it missing on his PCB and "correct the mistake" .

If you read this forum everyday as I do, you'd have seen many posts by users worried that "some parts are missing in the PCB" and need to be reassured that *their*  version does not need them.

Besides that, I post trying to explain things to the average user of this Forum, doubly so noting schematic details which might be confusing to an often inexperienced Forum member.

Try to get here more often, you edited without even asking my post from March 15 ....  2013 !!!!!!!  , one full year ago !!!! 

Next time use your fingers to write your own posts, no need to mess with other's.

[teemuk]

Please explain WHY do you edit MY posts without asking? :loco

Sorry. I was meant to quote it but I accidentally seem to have pressed the modify instead. I noticed the accident only was I had sent the message and started to wonder why the new post didn't show up. At that point it had already been "edited". The only edit to it is that I removed my post from the bottom. Once again, I'm sorry for this.

[g1]

JWOPT1 on page 1 and JWOPT2 on page 2 are definitely options that are in  place depending on whether the amp is the combo or head version.
However, the straight line short between the speaker leads (pg2, between bottom of C26 and left side of OPT2) is some kind of typo.
  If it even exists, it should be drawn as another optional jumper.