Noob needs help with z5600a II mic repair

[RoadrunnerOZ]

Also the schematic seems to show 1MΩ but maybe there was a design change and the schematic is out of date or the schematic is newer than your mic showing a mod. Only SE can tell you that.

 

[Adam Frandsen]

Also the schematic seems to show 1MΩ but maybe there was a design change and the schematic is out of date or the schematic is newer than your mic showing a mod. Only SE can tell you that.

I already contacted sE twice and they answer fast but refer me to the local distributor - I am already in contact with him, and he doesn’t have a schematic.

 

[Adam Frandsen]

Just because it would make me feel better. Important question though, R4 seems to be 1K in the z5600a schematic and maybe 3.9K in the blurred z5600a II schematic, is 1K the right value?

In the mic similar to mine found online it has black,black,black,white,brown resistor, sombasically a jumper?

 

[RoadrunnerOZ]

Agree with you there - just had a search through and Digikey are limited in what they have - also most of them are bulk pack or out of stock. I use Mouser as they’re quick as well. For me if RS Components or Element 14 don’t have local stock as both are near me Mouser is my next choice. 1/2W should be more than enough for R3

Should read R5 not R3 - sorry - the one with the two resistors tacked together supposed to be 300KΩ

 

[Adam Frandsen]

Thanks again for all the continued help with this unraveling DIY project. I really appreciate all I am learning here!

 

[RoadrunnerOZ]

Not a problem. I’d also check the voltage across the pattern switch in the PSU there should be 120V between the ground and top of the switch and 60 at the centre pole with the brown wire. Your HT+ should be 180V - if these voltages are out you may have failing Zeners - this is common in lots of different tube mics I have serviced - the Zeners working but locking a wrong voltage. The last one I did had the Zener chain giving 138V on a supposed 120V pair - one had 63V, one had 75V so I replaced them both - from the supply diagram you have 3 Zener diodes providing 60V centre pole voltage-lock on pattern SW, 120V top of pattern SW, 180V HT+
Edit: each Zener would be a 60V device

 

[RoadrunnerOZ]

In the mic similar to mine found online it has black,black,black,white,brown resistor, sombasically a jumper?

No, you’re reading back to front - the larger gap is between the fourth numerator which is the multiplier and the tolerance band at the end - it looks like orange, white, black, black, gap, black. The colors are alway washed out on metal film resistors due to the blue color behind the band colors. That photo of that other mic doesn’t show the resistor colors well. If what I see is right that’s a 390Ω resistor. Yours is orange, white, black, red - 3K9.
If you look at the 270KΩ resistors on the othe mic photo the red is different to what you see as red on R4

 

[RoadrunnerOZ]

Also yours has a 3K9, the schematic has tiny numbers which appear to be 3. 9K - big gap in the middle of the numbers.

 

[Adam Frandsen]

No, you’re reading back to front - the larger gap is between the fourth numerator which is the multiplier and the tolerance band at the end - it looks like orange, white, black, black, gap, black. The colors are alway washed out on metal film resistors due to the blue color behind the band colors. That photo of that other mic doesn’t show the resistor colors well. If what I see is right that’s a 390Ω resistor. Yours is orange, white, black, red - 3K9.
If you look at the 270KΩ resistors on the othe mic photo the red is different to what you see as red on R4

Thanks, was very tired last night, so brain wasn't working right. Too late to be looking at these things.

 

[pucho812]

This may be rude of me especially since I have been out of the loop on this for 4 pages of thread, but is there any way we could actually hear the mic as it sits?
It is working and all.

 

[RoadrunnerOZ]

Thanks, was very tired last night, so brain wasn't working right. Too late to be looking at these things.

All good. It is possible that due to bad light, metal films hard to read due to colors on blue and not such a good photo that the 2nd black band is actually red - making it a 3K9 on the other persons photo of the same mic

 

[terry setter]

I suggest you contact microphone-parts.com and buy one of their excellent upgrade kits that will fit right in. You'll end up with an improved mic, (though I love the Z5600's mechanical design).

 

[RoadrunnerOZ]

I suggest you contact microphone-parts.com and buy one of their excellent upgrade kits that will fit right in. You'll end up with an improved mic, (though I love the Z5600's mechanical design).

Just looked on microphone-parts.com and nothing there for SE, nothing under Z5600 either. Shame as it seems they cover a lot of mics too.

 

[Adam Frandsen]

The rest of the parts are on their way, desoldered some more of the resistors last night. The two 1 MegaOhm resistors were all 270k resistors one measuring 1.1k, the 100uf caps measured 84uF, the 300K was two 150k in parallel so 75k, the 51Megaohm resisitors are 22Megaohm measured, the 200Megaohm has a long, deep burn mark along the side from a soldering iron… those are the obvious faults so far

 

[Adam Frandsen]

Desoldered all except the ones that are clustered together, before doing so I want to make sure how to do it best, and be sure I can solder them together like that again. Also cleaned the PCB as best as possible...

 

[RoadrunnerOZ]

Desoldered all except the ones that are clustered together, before doing so I want to make sure how to do it best, and be sure I can solder them together like that again. Also cleaned the PCB as best as possible...

Looks like all your components are way out of whack. The cluster solder points are best approached by tinning with fresh solder or adding some flux before heating, so the whole join goes liquid on heating and gently prising off the top layer first - just don’t put too much heat and burn the board or too much lifting force. Often people try to desolder a dry connection and the heat doesn’t transfer properly and so leaves a hard mechanical connection they are trying to tear apart, or they use a coarse metal tool to remove the legs of the components that sucks the heat away - best is a fine stainless steel probe or needle. One of those components remaining is the 1GΩ resistor which you won’t be able to measure - I presume you have sourced another? The 200MΩ is at the limit of your new meter also so I would suspect you may not get a sensible reading on that one if it’s drifted higher than 200.

 

[Adam Frandsen]

Looks like all your components are way out of whack. The cluster solder points are best approached by tinning with fresh solder or adding some flux before heating, so the whole join goes liquid on heating and gently prising off the top layer first - just don’t put too much heat and burn the board or too much lifting force. Often people try to desolder a dry connection and the heat doesn’t transfer properly and so leaves a hard mechanical connection they are trying to tear apart, or they use a coarse metal tool to remove the legs of the components that sucks the heat away - best is a fine stainless steel probe or needle. One of those components remaining is the 1GΩ resistor which you won’t be able to measure - I presume you have sourced another? The 200MΩ is at the limit of your new meter also so I would suspect you may not get a sensible reading on that one if it’s drifted higher than 200.

But what I am really worried about is soldering it together again... And yes, all parts are coming

 

[RoadrunnerOZ]

But what I am really worried about is soldering it together again... And yes, all parts are coming

I presume you mean where there are multiple items that are soldered to the one point. Solder the first component in leaving enough leg length to solder the next one, leaving enough leg length on that one to solder the third and so on. Use needle nosed pliers to do a half wrap of the leg of the new component around the exposed leg of the first one soldered insane for the next. Fit items so you can read the values off the side and also if possible the component number on the board visible from some angle.

 

[RoadrunnerOZ]

But what I am really worried about is soldering it together again... And yes, all parts are coming

Did you source a 1GΩ resistor with the parts coming?

 

[Adam Frandsen]

Did you source a 1GΩ resistor with the parts coming?

Yes, two different ones - one like you linked to but 1/2 (which is still bigger physically than what is there now) and one 1.2 watt that is actually a little
smaller, but with +-5% tolerance instead of 1%.. The 51Mohm ones were only available in one size, 18mm long, so will have to be creative with placement and float them off the board above the surrounding components, but it should be fine...