Welcome to Australia's only Vintage Radio and Television discussion forums. You are not logged in. Please log in below, apply for an account or retrieve your password.
Australian Vintage Radio Forums
  Home  ·  About Us  ·  Discussion Forums  ·  Glossary  ·  Outside Links  ·  Policies  ·  Services Directory  ·  Safety Warnings  ·  Tutorials

Vintage Television

Forum home - Go back to Vintage Television

 'Vintage' Toshiba portable no sound: searching for IC TA7176AP
« Back · 1 · 2 · Next »
 Return to top of page · Post #: 1 · Written at 6:56:06 PM on 27 August 2018.
Clockmeister's Gravatar
 Location: Albany, WA
 Member since 20 January 2012
 Member #: 1068
 Postcount: 25

My vintage Toshiba "portable" C-1815 has lost sound and I've verified that the TA7176AP chip is dead. Apparently this IC cross-references to AN241, CA3065, HA1125, KA2101, LA1365, LA3065, MC1358, ULC2168 and ECG712.

The set is in nice condition and has a decent picture and If a few $ gets it going again it will be worth the effort so if anyone has a suitable IC please let me know price and postage to 6330 WA.

I couldn't find a schematic online for this model either, so if anyone can help with that it would be greatly appreciated also.

TIA for any help.


 
 Return to top of page · Post #: 2 · Written at 8:07:03 PM on 27 August 2018.
Johnny's avatar
 Location: Hobart, TAS
 Member since 31 July 2016
 Member #: 1959
 Postcount: 317

I think from memory these are the output chips that have little wing heat sinks in the middle.
Will have a look tomorrow for you, I'd be surprised if I didn't have one or its equivalent.
I think even HMV used these in their c211 colour sets.

Just edited my post, may be wrong might have been in the sound detector, not the winged output chips. Anyway should have one.
JJ


 
 Return to top of page · Post #: 3 · Written at 8:51:21 PM on 27 August 2018.
Clockmeister's Gravatar
 Location: Albany, WA
 Member since 20 January 2012
 Member #: 1068
 Postcount: 25

No wing on this particular chip it's a straight 14 pin dip. Yes it's a TV IF detector/amp sound chip

Cheers.


 
 Return to top of page · Post #: 4 · Written at 10:01:30 PM on 27 August 2018.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 5176

 
 Return to top of page · Post #: 5 · Written at 12:00:32 PM on 28 August 2018.
Johnny's avatar
 Location: Hobart, TAS
 Member since 31 July 2016
 Member #: 1959
 Postcount: 317

Have had a look, but unfortunately no.
Lots with similar numbers.
WES Components Sydney have them for a few dollars, and I notice EBay has a lot at various ridiculous prices.
JJ


 
 Return to top of page · Post #: 6 · Written at 5:22:49 PM on 28 August 2018.
Clockmeister's Gravatar
 Location: Albany, WA
 Member since 20 January 2012
 Member #: 1068
 Postcount: 25

WES looks like the go, thanks guys for your help - appreciated.


 
 Return to top of page · Post #: 7 · Written at 10:34:10 AM on 29 August 2018.
Clockmeister's Gravatar
 Location: Albany, WA
 Member since 20 January 2012
 Member #: 1068
 Postcount: 25

Well I found some on Aliexpress, Under $3 for five, including postage.

Expectations are low but for $3... worth a punt. I'm in no hurry to repair it.
I'll post an update if and when when they arrive, if they are the real deal, recovered or new and if they work or not.


 
 Return to top of page · Post #: 8 · Written at 2:11:51 AM on 30 August 2018.
Robbbert's avatar
 Location: Sydney, NSW
 Member since 18 September 2015
 Member #: 1801
 Postcount: 1043

Just remember the chip probably blew up for a reason, so check nearby electrolytics.


 
 Return to top of page · Post #: 9 · Written at 2:48:49 PM on 30 August 2018.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 1269

Could have been CRT flashover, most likely cause. Not much you can do about that.


 
 Return to top of page · Post #: 10 · Written at 2:12:00 AM on 31 August 2018.
Clockmeister's Gravatar
 Location: Albany, WA
 Member since 20 January 2012
 Member #: 1068
 Postcount: 25

I have already replaced the electrolytics in the audio circuitry already as a precaution and I'll replace the main filters too I think.
I'll see how it goes beyond that.


 
 Return to top of page · Post #: 11 · Written at 1:50:54 PM on 31 August 2018.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 1269

The original large can electros in that TV are probably better quality than any replacements you might use.I wouldn't bother.


 
 Return to top of page · Post #: 12 · Written at 10:49:00 AM on 9 September 2018.
Clockmeister's Gravatar
 Location: Albany, WA
 Member since 20 January 2012
 Member #: 1068
 Postcount: 25

I removed a few of the caps and tested them. Capacitance and ESR seemed bang on so they went back in. I'll assume all the others are OK.
Another problem I have now found is that the kids say they can hear an irritating high pitched sound when it's on. I did a check and it's the 15kHz... which of course the more mature members of the family can't hear. Sigh...


 
 Return to top of page · Post #: 13 · Written at 7:03:23 PM on 9 September 2018.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 5386

All CRT televisions and monitors emit a resonating noise, I assume from the tripler or its associated circuitry. I can hear it loud and clear despite partial deafness. Though if it is louder than usual, it may mean something is under stress.


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 14 · Written at 7:09:43 PM on 9 September 2018.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 5176

Flyback noise presumably. I can't hear it that well these days either, but I gave my analogue TV away to a worthy cause a while ago.


 
 Return to top of page · Post #: 15 · Written at 10:43:42 PM on 9 September 2018.
Robbbert's avatar
 Location: Sydney, NSW
 Member since 18 September 2015
 Member #: 1801
 Postcount: 1043

I used to be able to hear that whistle from TVs, but now with the tinnitus, the noise is there all the time, together with many other noises.

In my younger days I was able to hear it in the street, as I walked past houses with the TV turned on. Not any more.

The noise, I believe, is emitted by the line output transformer, and perhaps the picture tube and yoke too. It was absolutely deafening close to the back of a TV.

I only have one CRT TV left to annoy me, plus some CRT computer monitors which run at a higher (inaudible) frequency.


 
« Back · 1 · 2 · Next »
 You need to be a member to post comments on this forum.

Sign In

Username:
Password:
 Keep me logged in.
Do not tick box on a computer with public access.