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Just finished my DAC (1541A) , but 無聲出. Need Help!!!

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sjsiubong 發表於 2008-9-6 16:32:07 | 顯示全部樓層 |閱讀模式
Just finished my DAC 1541A kit, checked all the voltages
L1 = 5V
L2 = -13V
L3 = -5
L4 = 5
L5 = 5
L6 = 5
C29 = 15V
C30 = 15V

All chips sit ok in the IC sockets. I have made sure pins sit inside the sockets
用CD player's coaxial 連到 DAC1541A,  無聲出.
再 用CD player's coaxial 連到 另外Lite DAC, 有聲出.
用我的示波器check output. 看見有Hi frequency output, 但不像audio.
有 無人可幫一下??
Thank YOU!!!!

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kk_ho 發表於 2008-9-6 21:17:39 | 顯示全部樓層

Re: Just finished my DAC (1541A) , but 無聲出. Need Help!!!

Bong,

L1 = 5V OK
L2 = -13V (Problem, should be -15V)
L3 = -5
L4 = 5
L5 = 5
L6 = 5
C29 = 15V
C30 = 15V

TDA1541A have 3 diff voltage need.
+5V
-5V
-15V

KK
 樓主| sjsiubong 發表於 2008-9-9 07:41:27 | 顯示全部樓層
I will double check the voltages again.

What else do I need to check?

Is it possible that I have a bad TDA1541 chip?

Thanks,
Bong
kk_ho 發表於 2008-9-9 11:10:48 | 顯示全部樓層
Chance is less less....

All of the chip will test it before sending to overseas.
 樓主| sjsiubong 發表於 2008-9-10 02:36:39 | 顯示全部樓層
I have double checked all the voltage again.

L1 = +5V
L2 = -13.6V
L3 = -6.5
L4 = +5
L5 = +5
L6 = +5
C29 = +13.9V
C30 = -13.6V

Output of the power transformer marked 16v - 0v - 16v.
I measured that 20v - 0v - 20v.
After the diode,
I got 26V.
R11 = 13.9V
R12 = 12.7V
R13 = -13.7V
R14 = -12.4V

I will try to get some VR to replace the 2.2K resistors to get -15V.

So, the TDA1541 won't work if the voltage is lower than -15V? I The Spec said the min Voltage is -14V.  

What else should I try?

Thanks,
Bong
kk_ho 發表於 2008-9-10 12:21:44 | 顯示全部樓層
Step by step:

1. input the digital signal into DAC
2. Plot the waveform of CS8414
Pin 11,12, 19,26 to me.

Pin 7 and 22 should be 5V.
 樓主| sjsiubong 發表於 2008-9-11 13:42:52 | 顯示全部樓層
I have checked 8414 pin 7 and 22 are both 5V.
I have added 3 VR to get 15V now and I still have the problem.

I have added all the pix that you want. I added 4 more.
For the coaxial input and TDA1541.

Thanks!
BOng

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kk_ho 發表於 2008-9-11 19:19:39 | 顯示全部樓層
Please feed the coaxial signal direct to CS8414.
Skipping any pulse transformer and coupling cap.

Your CS8414 no data out !!!
thomasfw 發表於 2008-9-11 23:40:51 | 顯示全部樓層
I have bought 3 kits from China before
My experience was :
1) There was a ONE wrong location marking with the "Component Mark"  of 1.8K resistor. This made it open with the Opamp IC. But it only happen to one channel. (New ver. might already corrected)
2) Do you know that :

CS8412的21脚阻容选择为R25,C33,C35
一,选择R25装1K,C33装0.047,C35不用装
二,选择R25装470欧,C33装0.22,C35装3300P
 樓主| sjsiubong 發表於 2008-9-12 02:13:52 | 顯示全部樓層
Hi KK sir,
  I will try feeding the coaxial signal direct to CS8414.

For Old Boy,
   I am using
R25 --> 475R
C33 --> 0.047uF (Could not find 0.068 in the parts. Found only 0.047uf)
C35 --> No component. for my CS8414 PLL filter.

Thank you all!!
Bong
samuelsum 發表於 2008-9-12 11:04:20 | 顯示全部樓層
請問大家係咪講緊同一套kit :?:

我知道香港有另一個人賣; 大陸就無一樣既kit 賣

你可否拍照, 例如o的線既接法 ... 會唔會input組線有問題 :!:
thomasfw 發表於 2008-9-12 13:35:53 | 顯示全部樓層
[quote:c865fcc707="Sam_Sam"]請問大家係咪講緊同一套kit :?:

我知道香港有另一個人賣; 大陸就無一樣既kit 賣

你可否拍照, 例如o的線既接法 ... 會唔會input組線有問題 :!:[/quote]

From here :

http://bbs.hifidiy.net/viewthread.php?tid=157588&highlight=TDa%2B1541
 樓主| sjsiubong 發表於 2008-9-12 14:36:16 | 顯示全部樓層
I just tried to feed the coaxial input directly to CS8414.
I got the same result as before.

Do I have a bad CS8414 chip?

OR

I am using
R25 --> 475R
C33 --> 0.047uF (Could not find 0.068 in the parts. Found only 0.047uf)
Is it ok if I use use 0.047 instead of 0.068?

Thanks,
Bong

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 樓主| sjsiubong 發表於 2008-9-17 23:59:26 | 顯示全部樓層
Any more suggestions?
Any more pin out do you want to see?

Is it ok if I use use 0.047 instead of 0.068 for C33?

Thanks,
Bong
 樓主| sjsiubong 發表於 2008-9-24 00:42:05 | 顯示全部樓層
Have anyone made this DAC Kit work with CS8414 before?
I found some errors of this DAC PCB.

1) The Digital Ground of the CS8414 (Pin 8 DGND) is not connected to Ground.
2) C31 Cap 0.01uf is not connected to ground either.

Bong
kk_ho 發表於 2008-9-24 10:32:58 | 顯示全部樓層
Bong,

Please check with the diagram. And connect as like this.

RE-plot the waveform again and show it.

FYI:
We have 3 class about using this board also no problem, can you use our supplied components to assemble first, once OK, you change to yours as you like.

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mak_cw 發表於 2008-9-24 14:45:02 | 顯示全部樓層
From the figure 23, one end of the 75R need to be ground. So the junction between RXN and 75R need to be ground. Please check.
 樓主| sjsiubong 發表於 2008-9-25 02:02:06 | 顯示全部樓層
Did other people need to make this change too?
This change looks a bit difficult to make on this PCB, but I will try.

Would that be just a bad CS8414?

I have another DAC using the same CS8414. I will use this chip on the other DAC to check if the CS8414 is good or not.
I didn't do that before because the other DAC Kit is very expensive.

Thanks,

Bong
kk_ho 發表於 2008-9-25 11:51:47 | 顯示全部樓層
Bong,

I need to point out the TDA1541A KIT is work, no bug and mistake on the board. If you need to use DIR9001, it need some modification.

That why I tell you using the default components to power on the board first.

The chance of the CS8414 dead is lower.
autumnleaf 發表於 2008-9-25 15:42:41 | 顯示全部樓層
BongCalifornia,

You are so lucky to own a vintage Tek 465B scope. May I know how can get an analog Tek scope such as 2445 cheap but without risk?
 樓主| sjsiubong 發表於 2008-9-26 00:59:46 | 顯示全部樓層
Finally the DAC works now.
Thanks for everyone's help. Especially KK Sir!

Here is what I did.
Yesterday, I went to buy a 0.068uf cap.
I couldn't find the 0.068uf cap in the kit, so I used the 0.047uf that came with the kit. That is why the CS8414 could not lock the input signal.
I changed the C33 to 0.068uf. Everything works now!!!!!!
I didn't know that small difference can change the PLL filter that much!!!


For autumnleafacat:
I bought Tek 465B scope on Ebay for $60 USD.

Thanks again!!!
Bong
kk_ho 發表於 2008-9-26 01:36:39 | 顯示全部樓層
Bong,

Good work.

But I saw you have capacitor in your first post.....(the small brown color one)

One word to said, (not cannon after the horse)

See the photo.

I will ask admin to send out the notes. (by reduce the size first)

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 樓主| sjsiubong 發表於 2008-9-26 02:08:46 | 顯示全部樓層
Troubleshooting this DAC kit was painful and also fun.
I have learned a lot more this way. (Happy!)

It's fun to use the scope to probe each pin and make sure each Chip is working ok.  I had no idea of CS8414 before. Now, I have a little more ideas what each pin should output. Reading the schematics of this DAC and pin-out of each Chip was a good learning experience.

Now I can help other to troubleshoot this kit!!!!

Thanks HiFiever!!!!!!
Bong
alfcat 發表於 2008-9-26 08:27:23 | 顯示全部樓層
Just want to say "HI" to autumnleafcat,

I love your British Shorthair. I have dreamed of having one but just can't afford the price.

CAT
alfcat 發表於 2008-9-26 08:43:38 | 顯示全部樓層
Dear BongCalifornia & autumnleafcat,

Mine is also Tek 465B. Wow, Bong got it at US$ 60? I got mine here in Hong Kong at HK$ 1,200 around 6 months ago!

CAT
 樓主| sjsiubong 發表於 2008-9-26 09:42:12 | 顯示全部樓層
Hi AlfCat,,
  HK$1,200 is not too bad .
  I bought mine 2 years ago. I really used my scope this time for the DAC kit.  I just played around and learned to use it. I can't live without it when DIYing.
  I can't wait to work on my next audio kit project. Hope Hififever makes more kits!!!

Bong
autumnleaf 發表於 2008-9-26 12:45:34 | 顯示全部樓層
Hi, alfcat,

I breed the female BSH as shown. She won lots of prizes in cat show.

May I know where to buy a trusty analog Tek scope in Hong Kong. I also search on ebay for a 2445 150MHz 4ch scope. But the shipping charge cost as much as the scope. I had been 2nd hand test eqiup shop in KwunTong and Mongkwok. They told me some Tek scopes are broken and they sell it "as is" even at HK$10,000. I wondor I could get a Tek analog scope in good condition at a fair price in local.
autumnleaf 發表於 2008-9-26 12:53:41 | 顯示全部樓層
My cats at a glance. Some of them have their new homes in Hong Kong, US, Australia, Malaysia, Canada. They are all the stars in cat shows.

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alfcat 發表於 2008-9-26 20:51:47 | 顯示全部樓層
Dear Autumnleafcat,

Wow, you are a cat breeder? There aren't too many BSH breeders in Hong Kong. Your cats must be very expensive.

I got mine at eBay too. Fortunately, he is located in Hong Kong. I can only recall his name as Mr. Tam. He sells a lot of analog equipment like the Tek Scope. Unfortunately, I can't dig back the information from eBay anymore.

You are right in a sense that shipping to Hong Kong cost as much as the scope itself. I was kind of lucky that time when I got mine. Unfortunately, he didn't give me a card. Will see if I can locate him for you ....

CAT
autumnleaf 發表於 2008-9-26 21:36:07 | 顯示全部樓層
Hi alfcat,

Oh I see, I think I have more confidence on buying Tek analog scope on ebay now. Just be patient on looking for any Hong Kong sellers.

Thanks for your advice ....

But I also notice the vintage Tek analog scope is being more and more expensive now. Just like the fine and rare of Bordeaux .....
alfcat 發表於 2008-9-27 15:37:42 | 顯示全部樓層
Hi autumnleafcat,

Do you do cat breeding for a living? I guess your cats worth a lot of money.

Yesterday, I double checked all ebay sellers selling TEK scope already. can't find the one I dealt with ....
:cry:

CAT
autumnleaf 發表於 2008-9-27 20:36:48 | 顯示全部樓層
Dear alfcat,

Similar to hifi audio, breeding cat is only my hobby. However the adoption charge can cover the expense of attending shows.

Thanks for your help on my Tektronix analog scope searching. I will keep my eyes open on ebay once the Hong Kong seller surface.

You know the Tek 465 is the last scope they made using standard IC, which is maintainable lifetime, even including the CRT. For the analog scope mft after the 465, Tek used custom IC that the scope can be serviced as long as old stock custom IC last. Once broken, all finished.
alfcat 發表於 2008-9-28 09:13:39 | 顯示全部樓層
Dear autumnleafcat,

I thought of a last resort ---- I dug up my emails to search for the invoice the eBay seller sent me for payment. Wa La ... it is there!

I sent an email to him asking him whether he got more of those Tektronics scope or not. On his current listing, he got other stuffs but not oscilloscope.

Hope to get you good news later.

CAT
autumnleaf 發表於 2008-9-28 13:41:42 | 顯示全部樓層
Dear alfcat,

Thanks for your help.

All guys pursue old Tek analog scopes because only analog scopes tell the truth. The component datasheet only shows waveform photos taken from analog scope, but not using data captured by digital scope. The Aliasing Error in digital scope limit the accuracy of high frequency information when in slow time-base. This was my past experience.
alfcat 發表於 2008-9-28 22:28:27 | 顯示全部樓層
Dear autumnleafcat,

The seller IVAN says he got two other Tektronics scope for sale ($1500 to $ 2500, depending on model). You tell him you are Alfred's friend at St. Joseph's and you know that I have bought the 465B from him somewhat around June this year.

Please send me an email at achan@sjc.edu.hk and I can forward Ivan's email to you. You two can deal directly because I don't know what model suits your need.

Hope this helps.

CAT
autumnleaf 發表於 2008-9-30 00:17:38 | 顯示全部樓層
Thanks a lot. I will check within these days.
abelwoo 發表於 2008-12-22 10:41:13 | 顯示全部樓層
hi i wanna ask is this is 8x over sampling can it be modified to non-oversampling
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