Mainline Questions

[Paul Birkeland]

can you provide some constructive feedback please

The 1N5820s and the 5W resistor have not been heated enough to be properly soldered. 

 

[Paul Birkeland]

The bigger a part is, the more heat you need to apply to get the solder to flow out properly.  The two big resistors on your C4S boards in the R2 positions need more heat for the solder to flow out properly, and the MJE5731A transistors also need a lot more heat.  You can set your iron on one of these solder joints, add a little bit of solder, then count to 5, then pull it off.  You'll also see the solder suck into the board at some point when it has gotten hot enough, and you want to leave the iron on just a little longer after that happens.

 

[Tabaia]

Hello Paul,

I just wanted to ask a question regarding the first volt rest for the Mainline.
A little confusing as we are on 240V here in Australia.
My test read 247V.
How should I proceed?

 

[Tabaia]

Actually its 275V

 

[Tabaia]

After turning a few pages I found the 240 V section.
Mostly its around 245 V so I have opted for that connection.Greater than 235V and less than 245V.
But the power her varies a lot. still it seems that is the best optioj.
Let me know if that is OK.

 

[Tabaia]

Now I did the snd Voltage test with no reading?
Hmmm what have I done.

 

[Tabaia]

The Volume switches,

These are not straight.
So they are out of alignment.
Please see photos, any suggestions will be welcome to fix this.
I measured with a calliper The bottom of the shaft near the screw measures just under 82mm and the top measures just over 80mm so at least 1.5mm out of alignment.

Tunji

 

[Doc B]

There is a tab on the rotary switch where it goes against the panel, and a slot in the panel hole that the tab should be put into. Loosen the nut and turn the switch body until the tab drops into the slot, then retighten the nut.

 

[Paul Birkeland]

It looks like you might have the toothed lockwasher on the attenuator switches in the wrong spot.  It needs to go between the nut and the panel for each switch.

Yes, wiring for the 240V nominal primary when you have 247V is the way to go.

No voltage on your transformer test would have me looking at whether the fuse is installed properly in the IEC power entry module.

 

[Tabaia]

Absolutely Perfect 
Test all excellent and switches installed properly.
Thank you.
Your experience is invaluable.

 

[Tabaia]

275V test.

Reads 366V

What to do?

 

[Paul Birkeland]

What AC line voltage did you measure and how did you wire your power transformer primary?

 

[Tabaia]

What AC line voltage initially measured between 230 and 247
I used the wiring for Greater than 235V and Less than 245V.

Also Reading the manual and getting my head around this i realise that the reading I have for the board 235V is probably OK.
Manual says it should read between 300-500VDC , mine reads 366VDC.
I assume that is fine?

 

[Paul Birkeland]

Yes, all is well.  The voltage at that node will be relatively high when there's nothing built in the amp to load it down.

 

[Tabaia]

Great !Im on track.
Thank you.

 

[Tabaia]

Hello,
I have finally come to the point of checking the Ohm's
Here are my current issues:
Mostly where it say 0 - my multimeter reads Ohm
And on terminals 19 & 22 i get a reading of 200Ohm's.

What could be the issue?

Looking forward to your response.

 

[Paul Birkeland]

Could you post some pictures of these readings as they appear on the meter?

 

[Tabaia]

Here are the readings of terminals 19 and 22

 

[Paul Birkeland]

That's 200K, which is 200,000 ohms.

 

[Tabaia]

Ok thanks Paul.
Are those readings ok for those terminals?
The m,anual says otherwise.