Yet another fuse problem. Two in one day.

Problem: Not all drivers are speaking in a Genelec 1037C loudspeaker.

Solution: I decide to check the built in amplifier first.  A check of all the fuses turns up a bad one.  The good thing about fuses is that before any over-current badness happens to the electronics, the fuse says “no more” and blows.  Its a cheap and easy fix.  It just so happens that the last two pieces of gear that went through the shop are protection fuse problems.  Fuses melt for other reasons, like blown output transistors, but in these two cases, I lucked into easy fixes and not major damage to the gear.

Tascam M2600mkII Console Not passing a signal

Problem:  Tascam M2600 MKII console is not passing a signal.  When I hook a noise generator to the input, nothing happens.  I do get 48V (or just under) out of the mic inputs as expected.  I’m thinking it might be a power supply problem.

Troubleshooting Steps:

1. Check the integrity of the cable from power supply to console.  Result: Its electrically good.  Plug it back in. The end going into the power supply is a little loose when connected to the box.
2. 
3. Check voltage output of the power supply.  This is a 15 pin cable.  Thankfully, the user manual has the output pin assignments.  Result: +5, +48 are fine, +-20 is not.  I don’t have an elegant way to measure the voltage.  The Multimeter probes are too big for the 15-pin cable. I have to improvise with paper clips, being extremely careful not to short out the supply and blow something else!
4. 
5. Open the hood. The W2 Fuse looks suspicious.  Continuity test: Fuse fails.
6. 
7. Replace fuse.  I don’t have a 4A 250 volt 5x20mm package, slow-blow fuse so I insert a 2A fuse for a quick test. It works.
8. 

Time to order the correct fuse. I suspect the power supply cable was stressed enough to almost break it, and in the process, the 20V supply shorted out and blew the fuse. The evidence does point in that direction with a partially broken connector.  Either that or Pruis Hall was really rockin’.

Pinout Questions?

Today, I needed to know the pinout for a s-video connector. Electrical pinouts show you how connectors or cables are wired.  Here is the really handy website where I found the pinout for the s-video connectors.  www.allpinouts.org