Author Topic: newbie mistake wrong fuse  (Read 1646 times)

0 Members and 1 Guest are viewing this topic.

Offline alloby

  • Contributor
  • Posts: 24
  • Country: gb
Re: newbie mistake wrong fuse
« Reply #25 on: December 19, 2017, 11:24:07 am »
Thanks I will check that cap tomorrow and let you know is it best to check out of circuit .
 

Offline Paul Moir

  • Frequent Contributor
  • **
  • Posts: 842
  • Country: ca
Re: newbie mistake wrong fuse
« Reply #26 on: December 19, 2017, 11:34:09 am »
Check it in circuit first.  You may see your multimeter numbers climbing up as the capacitor charges if everything is good.  There are very few (no?) cases where a capacitor is shunted by a low value resistance.
If you do get a very low resistance then think about taking it out, but I would suspect the load that this capacitor is smoothing the output of the bridge rectifier for rather than the capacitor itself.
 

Offline alloby

  • Contributor
  • Posts: 24
  • Country: gb
Re: newbie mistake wrong fuse
« Reply #27 on: December 20, 2017, 01:12:29 am »
I need to read up how to check it properly also can anyone tell me if a rwm 6x 22 RB57 will be ok instead of rwm 4x22 RB61 I am having trouble finding a RB61 but RS stock RB57 thanks in advance.
 

Offline alloby

  • Contributor
  • Posts: 24
  • Country: gb
Re: newbie mistake wrong fuse
« Reply #28 on: December 20, 2017, 02:04:25 am »
I checked the capacitor its a 47micro farad 400v and off the board it reads 52.6 micro farads and it charges up and discharges so I assume it is ok.I also reversed my leads and still read 52.6 micro farads.
« Last Edit: December 20, 2017, 02:23:03 am by alloby »
 

Offline alloby

  • Contributor
  • Posts: 24
  • Country: gb
Re: newbie mistake wrong fuse
« Reply #29 on: December 20, 2017, 03:14:57 am »
I have just doubled checked bridge rectifier and I had a measurement wrong

The bridge rectifier reads red probe on + black probe on 1st ~ =OL
                                      red probe on 1st ~ black probe on + =0.0550
                                      red probe on  1st ~ black probe on 2nd ~ =0.0546
                                      red probe on 2nd  ~  black probe on first ~  =OL
                                      red probe on -    black probe on 2nd ~ = 0.543
                                      black probe on -   red probe on 2nd   ~ =OL
                                      red probe on 1st  ~ black probe on  - = beep or 0.001 and black probe on 1st  ~ red probe on - =beep
                                      black probe on -    red probe on 2nd  ~ = 0.0543  this is now correct
                                      red probe on +   black probe on 2nd ~ =OL
                                      black probe on +   red probe on 2nd   ~ = 0.547
I entered it wrong first time so can anyone confirm it is still faulty
 

Offline Dbhrs

  • Newbie
  • Posts: 4
Re: newbie mistake wrong fuse
« Reply #30 on: December 20, 2017, 03:27:53 am »
I would say that one internal diode is shorted. So it is faulty

I don’t have very much experience with this so someone may say different.


Sent from my iPhone using Tapatalk Pro
 

Offline alloby

  • Contributor
  • Posts: 24
  • Country: gb
Re: newbie mistake wrong fuse
« Reply #31 on: December 20, 2017, 03:34:28 am »
Thanks I hope so I have double checked and that was the only one I had wrong
 

Offline WaveyDipole

  • Frequent Contributor
  • **
  • Posts: 275
  • Country: gb
Re: newbie mistake wrong fuse
« Reply #32 on: December 20, 2017, 07:49:04 am »
Yes, the rectifier is faulty. I was trying to ascertain whether it had become stressed by a short across the smoothing cap. Sounds like the cap is Ok so there must be another explanation for the rectifier failure.
 

Offline james_s

  • Super Contributor
  • ***
  • Posts: 6196
  • Country: us
Re: newbie mistake wrong fuse
« Reply #33 on: December 20, 2017, 12:41:33 pm »
Occasionally rectifiers just fail, I wouldn't spend much time looking for the fault. Especially in low cost Chinese gear it was probably spec'd for the lowest cost possible and may have been of questionable quality to begin with.
 

Offline ggkios

  • Contributor
  • Posts: 6
  • Country: gr
Re: newbie mistake wrong fuse
« Reply #34 on: December 20, 2017, 03:16:10 pm »
Occasionally rectifiers just fail, I wouldn't spend much time looking for the fault. Especially in low cost Chinese gear it was probably spec'd for the lowest cost possible and may have been of questionable quality to begin with.
Hes got a jbc, starting price for one is around 500$, but yeah i sometimes bridge rectifiers fail

???????? ??? ?? LG-D855 ??? ??????????????? Tapatalk

 

Offline alloby

  • Contributor
  • Posts: 24
  • Country: gb
Re: newbie mistake wrong fuse
« Reply #35 on: December 21, 2017, 03:43:12 am »
I have ordered the exact bridge rectifier part but I cant find exact resistor rwx422 rb61 6.8ohm 7w so I have ordered Vishay RWM 6x22 rb57 Series Axial Wirewound Resistor 6.8? ±5% 7W ±75ppm/°c I am thinking they will be ok so if anyone thinks they are not suitable let me know
« Last Edit: December 21, 2017, 03:48:08 am by alloby »
 

Offline alloby

  • Contributor
  • Posts: 24
  • Country: gb
Re: newbie mistake wrong fuse
« Reply #36 on: December 26, 2017, 02:07:21 am »
I have received new bridge rectifiers and after testing it confirms my one was faulty I am just waiting for resistors and will update when they arrive.
 

Offline alloby

  • Contributor
  • Posts: 24
  • Country: gb
Re: newbie mistake wrong fuse
« Reply #37 on: December 30, 2017, 03:17:43 am »
 I got my resistors in post and soldered it on board along with bridge rectifier put new fuse in and it works,I cant believe it so thanks to everyone who helped, to some it might have been an easy fix but to me I felt I was out of my depth but now I have more confidence in myself and it has helped me to think about what is happening in a circuit I feel I have learnt a lot and this forum is the reason why so again a big thank you and hope everyone has a prosperous new year.
 

Offline ggkios

  • Contributor
  • Posts: 6
  • Country: gr
Re: newbie mistake wrong fuse
« Reply #38 on: December 30, 2017, 03:24:21 am »
Glad it worked, hopefully it will stay this way
 
The following users thanked this post: alloby

Offline Gyro

  • Super Contributor
  • ***
  • Posts: 3511
  • Country: gb
Re: newbie mistake wrong fuse
« Reply #39 on: December 30, 2017, 04:00:19 am »
Congratulations on the successful repair alloby.  Best wishes for the New Year.
Chris

"Victor Meldrew, the Crimson Avenger!"
 
The following users thanked this post: alloby

Offline Dbhrs

  • Newbie
  • Posts: 4
Re: newbie mistake wrong fuse
« Reply #40 on: December 30, 2017, 10:22:50 am »
Congratulations and Happy New Year


Sent from my iPhone using Tapatalk Pro
 
The following users thanked this post: alloby


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf