Servicing Philips TV Tester 808/TVT
It must be somewhere around the mid of 1980s that I got a chance to include TVs in the range of electronic devices that I repaired. It was during that time, TV was introduced for the first time in Bangalore. Only B/W TVs were in the market at that time. After learning the technology from books and practical experiences, when I started house visits for rectification of defective TVs, it became necessary for me to have at-least the basic tools. That is how I bought this wonderful tool, Philips TV Tester 808/TV that has RF and Audio output, with signal level controls for both.
When we connect the RF output to the Aerial socket, we get thick bars on the screen, indicating that all is well with the TV! This was very useful, as in the beginning, transmission was not for 24 hours. It was restricted to a few hours in a day with breaks in between. Just like a Radio. As working on a set without Telecast Signal was required quite often, this tool has helped me trouble shoot many video and audio problems in TV as well as Amplifiers!
During one of my trouble shooting works on an Amplifier, this broke down recently, and I had to set that right before I could proceed further. I opened the Tester and you can see the inner parts:
On checking the transistors, which are the most likely components that could fail, I found out that all was not well with one BC148A transistor, which comes at the final stage of Audio output. So, removed it and tested it with my Peak Atlas, which showed the transistor was faulty:
Replaced it with a BC548, and checked the output in my oscilloscope and found that the signal was ok for this type of basic audio generator. The first picture below is that of Audio and second is of RF (There was no defect in this circuit), which is not a modulated signal:
So assembled it back:
It becomes necessary for almost all of us to trouble shoot our tools first many times, and this was one such. I thought of sharing this with you all, as this tool is a unique device, which may not be very common. Unfortunately, this was discontinued by Philips long back! The fact that it failed only after working for so many years, shows what was the quality of products available that time! I forgot to mention that I retouched all the solder joints and cleaned the PCB thoroughly as a preventive maintenance. This device does not use any electrolytic capacitors.
This article was prepared for you by Parasuraman Subramanian from India. He is 66 years old and has more than 30 years’ experience in handling antiques equipment Valve Radio, Amps, Reel Tape Recorders and currently studying latest techs classes conduct by Kerala State Electronics Technicians’ Association. He was a BBA graduate, retired as MD of a USA company.
Please give a support by clicking on the social buttons below. Your feedback on the post is welcome. Please leave it in the comments.
P.S-If you enjoyed reading this, click here to subscribe to my blog (free subscription). That way, you’ll never miss a post. You can also forward this website link to your friends and colleagues-thanks!
You may check on his previous repair article below:
https://jestineyong.com/servicing-chinese-retro-lantern/
(87)Dislikes
(0)
17 Comments
Leave a Reply
Paris Azis
December 30, 2016 at 10:55 pm
Hi Parasuraman
Good job. I have a newer model of Philips, almost like yours,which works fine up to now. It has only one volume adjustment and produces three signals. One audio signal,around 350Hz, and two RF signals. One at 5,5MHz and the other one preset at 4,43 for PAL color signal,adjustable also for SECAM signal transmission.
This handheld instrument was a universal signal injector. Exploiting harmonics it was useful in checking all the RF-IF and colour stages of a TV receiver. Audio output was also available for amplifier testing.
I bought it at the Era of B/W transmission, using it also during the Era of colour transmission. A marvelous handheld signal injector.
Thank you for this memory refreshing article.
Albert van Bemmelen
December 31, 2016 at 2:03 am
Thank you Parasuraman.
My equipment limits down to only one but quite expensive Leader Grid-Dipmeter (upto around 250 Mc/MHz). That can be used as a dedicated tool for RF modulated and unmodulated testtransmissions, and also be used to test filters (MF suction circuits, Quartz and other components etc.). When a filter sucks energy from the Griddipper transmitter coil it shows a Dip at that frequency of the Filter. And since I now own two 350 MHz Tektronix scopes I finally also am able to read the exact filter frequency and view the HF signals too! Which is great when you want to know if an oscillator really oscillates and at what frequency. And the Philips equipment in your article must have cost quite a lot too at the time.
Mark
December 31, 2016 at 6:08 am
Hey Parasuraman,
Well done on your repair. If we don't have our testing equipment in good state, it's pretty hard to do the actual repair. Sounds like a quality tool if it lasted this long with only a minor repair.
Ruben
December 31, 2016 at 12:51 pm
well done, how i wish to have a tv tester too
Yogesh Panchal
December 31, 2016 at 2:11 pm
Good job sir,
Keep up sharing.
reza
December 31, 2016 at 2:28 pm
Hi Parasuraman Subramanian
You're a good mechanic
nice to meet you
good luck
Robert Calk
December 31, 2016 at 4:22 pm
Nice job, Parasuraman. Thanks for sharing the repair with us.
suranga Electronics
December 31, 2016 at 6:22 pm
Hi Parasuraman,
Good Repair Job.
Thanks you.
Bulent NUR
December 31, 2016 at 6:49 pm
Good repair, thanks for sharing.
Tyrone
December 31, 2016 at 9:12 pm
Thank you Parasuraman for all the repair articles which you have shared with us
this year,and it is a joy to have persons like you with such knowledge around.
Happy New Year and may God continue to bless you.
Rob
January 2, 2017 at 5:30 am
Hi Parasuraman,
You mentioned that you replaced the faulty BC148 for a BC558. The latter is PNP, the BC148 is a NPN transistor.
Typo perhaps and you replaced it by a BC548?
Kind regards, Rob.
Parasuraman S
January 2, 2017 at 10:40 am
Yes, you are right. It was BC548 and not BC558. That was a typographical error. I request Jestine Yong to correct it in the article. Sorry for this mistake!
U.Beia
January 2, 2017 at 7:32 am
Thanks for your repair article.Hope to receive more in the new year and keep it up.
Ulises Aguilar Pazzani
January 4, 2017 at 12:26 pm
Mr Subramanian great job Sir
Beau Friend
January 7, 2017 at 1:09 pm
Hi Parasuraman, do you have a circuit diagram for the tester and if so, would you be willing to share it with us? Keep up the good work.
Parasuraman S
January 14, 2017 at 2:20 pm
Sorry, I do not have.
G A Vishesh
January 16, 2017 at 5:05 pm
Hats off to You Sir,
Hope if we had as much as patience that you have.
Thanks for the presentation