Hairball 1176 Power Transformer Question

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rockmonkey731

Member
Joined
Nov 9, 2012
Messages
23
Location
Denver, Co
Hey Everyone,
I've just finished putting together my Hairball 1176 Rev D, and seem to be having some issues with the Power Transformer. When I turned the unit on for the first time, the lamp light turned on and the meter started moving up, got to about -10, then everything died. Since then, nothing will turn on. The lamp light works, when I put a 9v battery on the terminals it turns on, so I'm assuming the problem is the only thing in between the power inlet and the lamp, the power transformer.

I've included a picture of my transformer color code and how I have it wired. I did it according to the mnats wiring page:
http://mnats.net/1176_reva-d_hairball_wiring_power_avel-lindberg.html

I'm guessing it's a color code issue, as he states what color to use for the primary windings, but not what each wire is. When he says which to use for the secondary windings, he does include the functions, and mine are coded differently than his.

Any help would be greatly appreciated.
 

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Ok, after doing some reading on the site, I think the issue may be my secondary wiring. The mnats wiring page says:
Identify the two "0V (centre tap)" wires coming from the power transformer secondary. On the Avel-Lindberg power transformer these are the red and orange wires of the secondary windings.

I have the Avel-Lindberg transformer from hairball, but maybe I'm misreading it. On my transformer (pic in the first post) are the 0V center tap wires the orange and black? Or red and orange? Because it seems that everyone is using red and orange as the center tap wires. Maybe I'm just misreading the transformer label, I'm pretty new to this stuff.

All that being said, would this error in wiring cause the fuse to blow? Or is there potentially a whole separate issue i need to look into?

Thanks.
 
HI ,

Exact same problem here. And my battery works with a 9 v as well. This happened today with my hairball rev d as well. Please let me know if you find a solution.  Same thing with the vu jumping to -10

Rich

 
By the way. I tested my rails before stuffing the rest of the board and wiring the lamp etc and it did read properly before it died so it was working properly at one time


Rich
 
Hi,

You were right. Fuse looked good but wasn't . Blew 2 more fuses and then got one to work long enough to test the rail which came up good. What would be causing the fuses to blow? Thanks in advance!!!!


Rich

 
Ok, I  tested my rails and everything is good. I switched my secondary wiring to be correct. I turned it on, and the meter got to about -3 before it died. My suspicion is that the fuse (250 mA) may be too low. Tomorrow I'll try a 500 mA fuse and see.

 
rockmonkey731 said:
Ok, I  tested my rails and everything is good. I switched my secondary wiring to be correct. I turned it on, and the meter got to about -3 before it died. My suspicion is that the fuse (250 mA) may be too low. Tomorrow I'll try a 500 mA fuse and see.
This is only one reason to better fill in a location in your profile when asking -whatever it might be 90/100/115/230/240VAC- mains voltage related questions in an intercontinental forum ...
Your 250 mA fuse rating is missing the fusing characteristic parameter (FI 250 mA / t) for the time lag/slow blow fusing characteristic needed to stand the toroidal transformers higher inrush current.
 
Ah, forgot about that  ;). Anyway, Im in the USA, so I'm running on 120 V. The fuses i'm using are are 250 mA @250 Volts, slow blow.

Here's a link to the ones I ordered in case more info is needed: http://www.mouser.com/ProductDetail/Schurter/00343111/?qs=sGAEpiMZZMseCiJT91fwIs9BkcYSNFq%252bjo2DDdhZEy4%3D\

Thanks a lot for the help. I'm quite a newbie at this stuff.
 
Hi,

Changing the fuse out fixed the power issue, lamp etc. I don't think the fuses from mouser are slow blow.Now I have no input level. Where is the best place to start as far as tracing the inout?

Thanks

Rich
 
rockmonkey731 said:
Ah, forgot about that  ;). Anyway, Im in the USA, so I'm running on 120 V. The fuses i'm using are are 250 mA @250 Volts, slow blow.

Here's a link to the ones I ordered in case more info is needed: http://www.mouser.com/ProductDetail/Schurter/00343111/?qs=sGAEpiMZZMseCiJT91fwIs9BkcYSNFq%252bjo2DDdhZEy4%3D\

Thanks a lot for the help. I'm quite a newbie at this stuff.
So this 30VA toroid with -from datasheet- 13.7% regulation would need a fuse with min.rating [ 30VA/120V*(1/(1-2*0.137)) ]=0.344A.
Next avail. standard fuse rating will be 400mA.
 
RichardM said:
Hi,

Changing the fuse out fixed the power issue, lamp etc. I don't think the fuses from mouser are slow blow.Now I have no input level. Where is the best place to start as far as tracing the inout?

Thanks

Rich

Which Rev are you using?  Please post follow up questions to the help thread of your rev to make things more searchable for others.

Have you done the Qbias calibration?
 
Hi ,

I am using the Rev D. The meter does jump sometime when it is turned on now but the new fuse seems to handle that initial burst better. I don't think that the fuses from mouser are slow blow. I haven't been able to calibrate because now it appears I have no input. How can I trace the problem on the input side? Thanks!!!


Rich

 
RichardM said:
Hi ,

I am using the Rev D. The meter does jump sometime when it is turned on now but the new fuse seems to handle that initial burst better. I don't think that the fuses from mouser are slow blow. I haven't been able to calibrate because now it appears I have no input. How can I trace the problem on the input side? Thanks!!!


Rich

You can't test the unit until you at least calibrate the Qbias.  If the bias is not set you could be dumping all of the input to ground. 
 
I tried to calibrate but when I turn up the input during the adjustment the vu meter won't move up to 0 db as it should. I did ground out pad 22 as it stated in the video. Now any suggestions?

Thanks

Rich

 
RichardM said:
I tried to calibrate but when I turn up the input during the adjustment the vu meter won't move up to 0 db as it should. I did ground out pad 22 as it stated in the video. Now any suggestions?

Thanks

Rich

I moved your question to the D thread for organization purposes.  Let's continue in there.

Mike
 

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