Intermittent Crackles and Pops

[Skip060]

I recently acquired a vintage PHILIPS B6X44a, I believe from the early 1960s. While the set plays well, all lights work, no static issues with controls, I do get intermittent crackles and pops on both FM and AM bands. I am a total novice at this so I wonder if someone can give me advice on what this issue might be and how I can troubleshoot it. Appreciate any help you can provide.

[bob91343]

Chances are, the capacitors are trying to fail. You are perhaps hearing a short occur, followed by self healing. You might as well start replacing them.

Does the problem occur at all settings of the volume control, or can you control its volume? I would attack the power supply first.

[old_coot88]

I wouldn't attack anything until determining whether the noise is 'upstream' or 'downstream' of the volume control.

[Nick_the_'Nole]

Does the popping/crackling occur only through the tuner, or do you get it on the external tape/phono input as well?

If it's only in the tuner, then it could be 'silver mica disease'.

[wa2ise]

If it's "silver migration" in the IF transformers, take a ;ppl at ,y page, halfway down http://www.wa2ise.com/radios/repair.htm
As a novice, you may not want to mess with the IFs just yet, maybe someone here lives nearby. I don't know what Philips did, but most all American makers used caps that were just a single mica wafer, with a pair of caps printed on it, side by side.

[Skip060]

Originally Posted by old_coot88

I wouldn't attack anything until determining whether the noise is 'upstream' or 'downstream' of the volume control.

I think it may be upstream since the crackle and pops occur at the same volume level even when the volume knob is turned all the way down.

[Skip060]

Originally Posted by wa2ise

If it's "silver migration" in the IF transformers, take a ;ppl at ,y page, halfway down http://www.wa2ise.com/radios/repair.htm
As a novice, you may not want to mess with the IFs just yet, maybe someone here lives nearby. I don't know what Philips did, but most all American makers used caps that were just a single mica wafer, with a pair of caps printed on it, side by side.

Oh boy, that sounds really intimidating. I wonder if anyone can recommend someone who has familiarity with European sets that I can take mine to to get it checked out.

[Skip060]

Originally Posted by bob91343

Chances are, the capacitors are trying to fail. You are perhaps hearing a short occur, followed by self healing. You might as well start replacing them.

Does the problem occur at all settings of the volume control, or can you control its volume? I would attack the power supply first.

It occurs at all setting of volume control even when it is totally turned down. Some time it occurs very infrequently and sometimes consistently for a while then dies down, and then starts up again.

[Electronic M]

Then it is likely not in the RF or IF and is probably in the power supply or the audio section.

[leadlike]

As long as you don't have a series-strung chassis (and since it is a european radio, you shouldn't) then you can pull the last tube in the rf section (before the audio amp) and see if the popping still remains. If it does, then you've likely got a problem with the audio/power section.

I'd just go ahead and recap all of the coupling caps, and replace the electrolytics, especially if you plan to use this set as a daily driver and want to leave it (relatively) unattended while it plays.

I don't know if European radios used the same crummy IF transformers that cause silver mica disease, but don't be intimidated: I just redid a pair of the exact same type that Wa2ise has pictured, and it took me a little over an hour to do the first time. 100 pf silver mica caps generally work well as replacements (Original values typically ranged from 50 to 150 pf). On my set, you could still turn down the audio, and the IF crackle would still come through, just not as loudly, but still audible enough to be heard across a silent room.

[Skip060]

Thanks all. I finally found the problem. It was the power tubes ECL86/6GW8s. I found used replacements and now it works just fine. Yeah!!