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 Kriesler 11-77/78
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 Return to top of page · Post #: 16 · Written at 8:35:46 PM on 9 April 2020.
Padge's Gravatar
 Location: Umina Beach, NSW
 Member since 9 April 2020
 Member #: 2410
 Postcount: 33

Okay so ive just looked at schematics and I think I have it worked out. I will replace all resistors and caps that you mentioned ian and then if I need to I will then go to petes idea of the speaker transformer and look at it from there. and if I need it pete I will email you if okay and get where I can have transformer rewired. or you can just tell let me know on my post here. thanks and have a great isolated easter.


 
 Return to top of page · Post #: 17 · Written at 8:39:07 PM on 9 April 2020.
Vintage Pete's avatar
 Location: Albury, NSW
 Member since 1 May 2016
 Member #: 1919
 Postcount: 2048

Speaker transformer either works or it doesn't.
You may have good ones . I'm not a techo ,I just have a liking for the 1177 so I play with them and restored it . So just follow Ian ,I'm just a drifter really,,pete


 
 Return to top of page · Post #: 18 · Written at 8:42:02 PM on 9 April 2020.
Padge's Gravatar
 Location: Umina Beach, NSW
 Member since 9 April 2020
 Member #: 2410
 Postcount: 33

Yeh thanks for your help. both speakers sound great. and I have schematics. I will replace all caps and resistors as mentioned by you ian. if no good I may then look at transformer although I'm hoping its not that.ive studied the schematics and I have replaced c22 and c23 and the 3 resistors that were around the c23. and thanks ian and pete I will let you know how I went.


 
 Return to top of page · Post #: 19 · Written at 8:44:43 PM on 9 April 2020.
Padge's Gravatar
 Location: Umina Beach, NSW
 Member since 9 April 2020
 Member #: 2410
 Postcount: 33

Haha pete ive been on the Krieslers for 3 years now but I'm only just getting into the electronic side of things now. I can rectify hum sounds now aand my soldering is getting better.


 
 Return to top of page · Post #: 20 · Written at 8:47:46 PM on 9 April 2020.
Vintage Pete's avatar
 Location: Albury, NSW
 Member since 1 May 2016
 Member #: 1919
 Postcount: 2048

Hey do you know Dany Mann's?
I use to live near you on Railway steet.
I live in Albury now , I'm sure may know Dan?


 
 Return to top of page · Post #: 21 · Written at 8:58:12 PM on 9 April 2020.
Padge's Gravatar
 Location: Umina Beach, NSW
 Member since 9 April 2020
 Member #: 2410
 Postcount: 33

No his name doesnt ring a bell. we have an antiques and collectables shop in umina beach. you can check out some of my radiograms that ive sold out of the shop. instagram #uminabeachupcycle ive had some beauties. and my name is shane, pete.


 
 Return to top of page · Post #: 22 · Written at 9:03:03 PM on 9 April 2020.
Vintage Pete's avatar
 Location: Albury, NSW
 Member since 1 May 2016
 Member #: 1919
 Postcount: 2048

Small world ,Dany ran the ettalong Antique shop called Nan's house, I Ran fab60s which was Sydney based .
Yeah ok check it out ,,Pete


 
 Return to top of page · Post #: 23 · Written at 9:13:56 PM on 9 April 2020.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 2369

Padge, there is a more scientific way of tracking down problems than just replacing parts until you fix it. Problem with this method is you WILL make a mistake and then you won't be able to find it. I'm sure Pete will concur!

For crackles, you need a 0.1μF cap with two clip leads attached. Use it to short the signal path to ground along the path. If the fault is after the cap, the crackle will remain.

Or of course if you have a CRO, just scope the path.

The secret of successful electronic servicing is "think with your head, not with your hands".

* Measure, gather evidence.
* Never change anything until you prove it's bad.
* The less you touch it, the less likely you are to break something that wasn't broken before.

Of course, with vintage gear, there are some exceptions, for example, if it's a wax paper capacitor, it's pretty much guaranteed to be leaky. If it's a mica cap that has a voltage across it, it will by now be exhibiting symptoms of silver migration and so for reliability reasons these things should be changed. (Don't bother changing mica caps that are connected across inductors and hence don't have a DC voltage across them, they will still be OK.)

The great thing about a stereo amplifier is you have two channels to compare.


 
 Return to top of page · Post #: 24 · Written at 9:20:26 PM on 9 April 2020.
Trobbins's avatar
 Location: Melbourne, VIC
 Member since 11 July 2012
 Member #: 1179
 Postcount: 56

A problem you will come across at some stage is confirming the two 6M5 are not too out of whack, as it is fixed bias (back bias) with no cathode resistors to easily check (so quick solution is to insert a 1 ohm resistor in each cathode). Quite likely the main reason so many output transformers go bust.


 
 Return to top of page · Post #: 25 · Written at 9:52:06 PM on 9 April 2020.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 2369

Another thing you may want to consider about the 11/77.

With a total HT current of around 80mA, the two amps and the tuner are running the 6V4 rectifier close to its maximum ratings.

You might want to consider replacing the 6V4 with a 6CA4, which is a plug-in replacement but is rated at 150mA.


 
 Return to top of page · Post #: 26 · Written at 7:59:26 AM on 10 April 2020.
Padge's Gravatar
 Location: Umina Beach, NSW
 Member since 9 April 2020
 Member #: 2410
 Postcount: 33

Vintage pete: oh danny yes I know him. we have bought a few things from him in the past. Thanks mate

Ian: thanks for the info mate I may need to google how to do what you propose. I am a learner at this and still do not have the skill level that some of you guys have. think with your head not your hands is a great philosophy. Ive only got a multimeter which is probably not the correct reading instrument which is why I asked the question hoping this forum would aid me in tracking this sound down. I'm going to learn to understand some things before I go forward. its a great machine just needs a tweek somewhere. Thanks for your ideas ian. they have opened my eyes up a bit.

Trobbin: cheers mate I really appreciate it.

are any of you guys happy for me to send a vid via email to you to hear the noise?


 
 Return to top of page · Post #: 27 · Written at 8:06:48 AM on 10 April 2020.
Padge's Gravatar
 Location: Umina Beach, NSW
 Member since 9 April 2020
 Member #: 2410
 Postcount: 33

Hey ian, ive just picked up on something you said. in your last post.i quote" the good thing about a stereo amp is there is 2 channels to compare". of course haha . cheers mate.


 
 Return to top of page · Post #: 28 · Written at 8:43:02 AM on 10 April 2020.
Vintage Pete's avatar
 Location: Albury, NSW
 Member since 1 May 2016
 Member #: 1919
 Postcount: 2048

Shane, most of those Kriesler chassis don't need much to get them going again.
And the 11 77 is a good one.
Mostly it's just a matter of replacing the paper caps and some resistors.
All you will need in a soldering iron and a multi meter.
But here is a good chance for you to learn enough to fix other radiograms you get your hands on .
The mistake people make when learning is they start replacing components that Dont need replacing and that's when things go wrong.
I'm guilty of doing that too.
It won't be needing a rebuild to fix it , it will be some paper caps and a mica caps and some resistors. So just hang in there and the jig saw will become clearer soon
Pete


 
 Return to top of page · Post #: 29 · Written at 9:57:54 AM on 10 April 2020.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5250

The main thing to remember with stereo amps is to not get enthusiastic & repair both simultaneously. If on radio and both amps have snap crackle & pop. the probability is the radio, or power supply.

The most likely NP cap to fail has always been the plate bypass on an output valve. I find Australian Mica caps extremely reliable. The clamped wafer type from around 1938 on are extremely robust. I usually leakage test them at 500V.

If its just overhauled watch out for dry joints I have an English HMV set converted for Australia on hold at the moment. One cap had an end floating and there was one almost shorted lamp. It was supposed to work & all caps tested (how so)? All but the new filters ended up in my bin and there were seven dry joints and a damaged non compliant mains cable so it and some other wire also ended up decorating the bin.

Scary.

Marc


 
 Return to top of page · Post #: 30 · Written at 10:06:38 AM on 10 April 2020.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 2369

As Pete said, all you need is a multimeter and a soldering iron. Plus a roll of politically-incorrect solder and a good pair of side cutters.

If you are planning to take on vintage gear that has been hibernating for a long time, make yourself a dim bulb tester (google it)

The capacitor and clip lead trick is very valuable for tracking down noisy stages and components. Used it a lot in the 70s doing warranty service on stereograms like the 11/77 plus solid state units.

When measuring voltages and resistors, remember that 20% tolerance (error) was normal in those days and won't affect operation.


 
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