Engineering Change Order (ECO)
for:
high
Date:
Name/Signature:
G. Degen
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Project: H&K Matrix 100
Combo HU0204 Head HU 0304
Issued by: RD Date: 13-Apr-06 ECO No.: 10
Receiver: [AXL China
[Norman Hua]
[Ningbo]
Description of affected item(s) / old denomination:
Stamer part-no:
Drawing no:
Supplier:
Reason of change(s) / new denomination:
New part
Alternative
Stamer part-no:
Drawing no:
Supplier:
End-Of-Life of currently used part
Replacement part for:
Comments / necessary changes:
SEE 3 Pages Attachment
CC: AXL USA
Kenny Kwan
External/Receiver‘s
part-no:
Supplier part-no:
Product upgrade
Other Reason: Failure Rate field too
External/Receiver‘s
part-no:
Supplier part-no:
[NO]
[NO]
[NO]
[NO]
1) Replace C64 and C65 from 220uF/25V version to 220uF/35V version
2) Replace Resistors R82, R83, R69, R70, R75 to VISHAY manufacturer AC 05 type, same value
3) Modify assembly method of resistors (see attachment), ensure mfctr. procedure prevents from
Resistor leads being bent during production process
4) Improve procedure of assembly of power transistors to heatsinks to prevent gaps resulting burnouts
5) Replace Caps C14,C48,C49 from 85 degree type to 105 degree type, same values for capacitance
and voltage
6) Replace FX modules to Chip-directly-soldered types instead of Chip-in-socket types
7) Additionally replace R105, R106 to VISHAY manufacturer AC 05 type, same value
8) Additionally correct assembly method of diodes D25,D26,D27,D29,D31 (see attachment)
Approved by:
Date: 13.04.06 Name/Signature: K. Ballhorn
QA approval (for safety relevant parts only): required
Confirmation by:
Document flow: RD (QS) QM Receiver
EngineeringChangeOrder_FM045.dot RD Revision B, 05.11.2004
Engineering Change Order (ECO)
<Inspection Conclusion and Suggestion About the Quality Problems Of
Matrix 100>
From: AXL Ninghai Factory Engineering Staff
To: Stamer Engineering Staff
Date: 04/11/2006
• Electrolytic Capacitors
1. In Matrix 100 original circuit design, the max. allowable operational
voltage is only 25V for C64 and C65, but the actually maximum voltage
applied to these to caps are +30V and –28V, which had led about 10%
machine appeared noisy. This is the major reason to causing the
humming noise. Unfortunately, our technical department didn’t catch
this small technical detail and did not do the inspection in time.
KB/BS:
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You are right. At this point a 35V type must be used. This is the first time this point came up, and so far we never had problems or any other
indication or information on this. It also did – fortunately – not cause
any additional problem. The “humming” amps, we or our partner abroad
received for repairing, could always be fixed by exchanging (mostly
damaged) C48/C49.
So we cannot understand that this the major humming problem, as you
are supposing. Please let us know how you proof this statement.
Anyway: This must be changed, we will send ECO for replacement to a
220uF, 35V type together with the other issues. Same size of cap !
2. The local supplier for capacitors C48 (4700uF/63V) and C49
(4700uF/63V) provided us with lower capacitance than standard, not
consistent characteristics, technical parameters are fuzzy. In addition,
in Matrix 100 original design, C48 and C49 actual running temperatures
were very closed to the specified maximum temperatures, which had
caused some little lower quality capacitors failed (about 1%). But if the
design had chosen 5600uF/63V 105 thermostable capacitor instead
of the 4700uF/63V, it should have been more reasonable.
EngineeringChangeOrder_FM045.dot RD Revision B, 05.11.2004
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Engineering Change Order (ECO)
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KB/BS:
A word on the temp spec on EL CAPS. The specification, 105 Celcius
(as an example) means: The capacitor, when operated at a permanent
(complete) body temperature of 105 degree (not somewhere outside),
has it’s standard lifetime and it’s standard capacity loss over the lifetime, in other words, the capacitor is not thermally overloaded, but behaves like specified at this temperature !
We do not recommend to use 5600uF, pls leave with 4700, but the
temp. class 105 C shall be – as agreed already – can be used , this gives more safety at no cost.
3. The ambient temperature around the capacitor C14 (2200uF/35V) is a
little too high. To choose 2200uF/35V 105 thermostable type is more
reasonable. Also, when the main board HU0204-LP-R01 under tested,
there is a possibility: that before JP8 not connected (IC U9 is connected
to the load), C14 actual running voltage can reach to 38V, this is also a
potential problem here. In addition, C14 is placed half-wave rectifier
D23 circuit path, which has large ripple current effect. This is also need
to be reconsidered for the design.
KB/BS:
Pls see remarks to thermal behavior above.
The test instruction – if followed - advises not to operate with no load,
so if watched by the personell, this wont be a problem. However, if higher voltage 38V accidentaly is applied for short time during test, this
should not do any harm to the EL Cap.
In general, we must select higher quality and standard of capacitors for
C14, 48, 49, 64, 65.
EngineeringChangeOrder_FM045.dot RD Revision B, 05.11.2004
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Engineering Change Order (ECO)
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• FX board:
During the production runs for Matrix 100, we have kept finding out the quality
problems of the FX board and alos feedback the problems to the FX (SEED)
supplier. However, SEED has not done much to improve the FX board quality.
Stamer engineering staff needs to discuss with SEED about the FX quality problem to obtain a solution for it because FX board did not perform properly is
not only caused by loosen controller chips in the sockets. And to solder controller chip directly may not have the problem solved.
KB/BS:
Up to now we did not receive any problem other than loose controllers in bad sokkets. IF you have evidence or good failure description of any other problem with the
FX boards delivered by SEED, pls let us know, inform also SEED directly for repairing or replacement, or investigation on systematical errors (if one type of error comes up more often)
• Power Resistors:
After a 100-hour test, found broken legs from some of power resistors that installed on the PCB of the Matrix 100 combo, but did not happen to Matrix 100
Head. So besides intensifying the strength of the legs, can you make some
changes of cabinet for Matrix 100 Combo: to place another baffle board in the
bottom of the chassis to help reducing vibration from cabinet to the PCB.
However, it might affect the sound effect.
KB/BS:
To introduce another wooden baffle board will change the sound massive, this is not
a viable way to go ! Your test results proof what we have found out here, so we need
definitely a better “leg quality” at least for the Combos, yet – logistically more easy to all Matrix products.
EngineeringChangeOrder_FM045.dot RD Revision B, 05.11.2004
Engineering Change Order (ECO)
• Remarks:
We are currently executing the improvements
1. Capacitors C14 ,48, 49, 64, 65 are being selected to get higher quality, and
higher class electrolytic capacitors from different vendors. All technical department staff are putting their greatest effect to control the quality of caps.
2. Increasing the number of procudures of making heat sink to make its surface
more smoothly and straight flat. So the power transistors will be placed on the
heat sink without any gaps or space. The assembly-step is being strictly overseen.
KB/BS:
Nr 3 of this should be the change of resistor manufacturer types.
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Thanks for investigation and cooperation so far !
We will send an ECO this week. It will include all of above.
St.Wendel, April 13, 2006
EngineeringChangeOrder_FM045.dot RD Revision B, 05.11.2004
Engineering Change Order (ECO)
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EngineeringChangeOrder_FM045.dot RD Revision B, 05.11.2004
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